Grey’s Anatomy: The 14 Most Shocking Cheating Moments, Ranked!

Relationships on the hit ABC medical drama Grey’s Anatomy have always been complicated, reflecting a myriad of complexities that human beings face in daily life, including infidelity, and even the most beloved couples, like Meredith and Derek, face cheating. Whether falling in and out of love, holding a candle for someone who’s beyond reach, as well as the dark, murky side of relationships, Grey’s Anatomy has shown it all.

Though Grey’s Anatomy began centered on Meredith Grey (Ellen Pompeo) and her class of residents, it expanded to include multiple generations of doctors and medical students. The relationships between all of those characters are explored in the series. The series is as much a relationship drama as it is a medical series, and the characters have been deeply in love, but they have also cheated on their partners and been unfaithful at various times. Some of these creative decisions completely threw the arc while a few made some sense in the broader context.

DID YOU KNOW: Every episode, except one, in Grey’s Anatomy is named after a song? The exception is a season 14 episode titled “1-800-799-7233,” which is the hotline for domestic violence.

14Jackson Avery On Maggie Pierce

Jackson Never Emotionally Let Go Of April

Jackson didn’t physically cheat on Maggie. That’s an important difference between Jackson and the rest of the Grey’s Anatomy characters who have cheated on their partners. Jackson is a very loyal person, which is part of the reason he maintains even platonic relationships with those he’s had romantic relationships with in the past.

When Jackson takes a break from Seattle, he spends time in a monastery and connects with another woman – while he’s in a relationship with Maggie. He stresses to Maggie that he didn’t cheat on her, but it still causes a rift in their relationship, one only strained further by him still maintaining regular contact with April, his ex-wife. Sadly, the couple had a rough breakup in season 16 when they admitted that they never really liked each other as much as they should have.

Maggie feels threatened by his emotional connection to these other women, and she’s not entirely wrong about Jackson. He might not physically cheat on her, but Jackson always has feelings for April, and he eventually ends up back with his ex-wife years after they divorced

13Owen Hunt On Emma Marling

Owen Had A One-Night Stand With Cristina

Although fans would hate to see some of their favorite characters be unhappy, that does not mean that they completely agree with their actions. There were plenty of fans who didn’t agree with the way Owen and Emma’s relationship ended, as Owen cheated on her after having a one-night stand with Cristina. This was terrible since Emma had agreed to be a stay-at-home mom, and they were planning to live together. However, Owen broke up with her after sleeping with Cristina, which was heartbreaking.

There were plenty of fans who didn’t agree with the way Owen and Emma’s relationship ended, as Owen cheated on her after having a one-night stand with Cristina.

From the fans’ perspective, this didn’t make a lot of sense. Cristina and Owen had already agreed that they didn’t belong together anymore since they wanted completely different things in life, so no one could understand why the writers were revisiting this storyline. What was even more frustrating was that Owen and Emma seemed quite happy together. It just felt like they were trying to find a way of getting rid of Emma quickly, but it just made Owen look really bad when it happened.

12Alex Karev On Izzie Stevens

Izzie Catches Alex Sleeping With Olivia

At the beginning of Grey’s Anatomy, Alex Karev was arrogant and selfish, and grossly lacked any social etiquette. He also ends up cheating on Izzie Stevens with the nurse Olivia after he lets the pressures of the burgeoning relationship get to him. Alex finds himself unable to commit and open up to Izzie, and he hooks up with Olivia instead. What even makes this worse is that Izzie catches Alex and Olivia in the act, and she immediately ends their relationship on the spot.

Although Izzie and Alex weren’t formally together at the time, they were building to something good. Izzie was also the person who convinced everyone to give Alex a second chance after she saw a softer and more vulnerable side to him. In that light, the fact that Alex fooled around with another woman while giving Izzie hope was not a good development for the character. In the end, Alex ended up going back to Izzie after he learned she had his child, but this moment was not his best.

11Nathan Riggs On Megan Hunt

Nathan Cheated On Megan Years In The Past

Nathan Riggs appeared only for a brief time at Grey Sloan Memorial. He was Owen Hunt’s ex-colleague in the military and the fiancé of Owen’s sister, Megan. When Nathan first showed up on Grey’s Anatomy, he and Meredith had a relationship. He never told anyone about cheating on Megan in the past, and he said it was no one’s business anyway. However, when Megan was found and brought to Seattle, Nathan wanted to get back with her, but it wouldn’t last the test of time.

Megan and Nathan were both revealed to have cheated on each other. However, Megan’s side of the story is never really shown explicitly, while Owen berates Nathan time and again for having cheated on his sister. He was even revealed to have gifted Megan a necklace belonging to the woman he had cheated with. Although he did move heaven and earth for Megan after she was found alive, his history of cheating couldn’t be erased.

10Addison Montgomery On Derek Shepherd

Addison Created On Derek With His Best Friend, Mark Sloan

Kate Walsh joined the medical drama as Derek’s wife, bringing up the third angle of the love triangle that Meredith and Derek originally found themselves in. But even as the thorn in Meredith’s flesh, Addison soon went on to be a beloved character, and fans couldn’t get enough of her. Addison was said to have cheated on Derek with his best friend Mark Sloan prior to the timeline of the show itself. Derek was dating Meredith Grey when Addison returned to his life, and he left Meredith to go back to her.

However, Derek cheated on her with Meredith and their marriage came to an end as a result. Of course, had Addison never cheated, the entire Meredith-Derek storyline might never have happened, but keeping that aside, it was pretty low of her to have an affair with her husband’s best friend. Neither of these people was faithful, and neither of them was happy until they finally ended their relationship for good and moved on in their lives. Addison shouldn’t have cheated, but this was never meant to be.

9Derek Shepherd On Addison Montgomery

Derek Cheated With Meredith Grey

If there were any fans who had actually thought that Addison and Derek could salvage their marriage, they soon lost all hope once Derek cheated on Addison – again. The two were going through a rough patch when the series began because of Addison cheating, and he hooked up with Meredith. They tried to make their relationship work, but Derek eventually cheated on Addison with Meredith again. It shouldn’t have come as a great surprise since it was evident that Derek was still in love with Meredith.

However, instead of telling Addison that their relationship wasn’t working for him anymore, he ended up sleeping with Meredith in the on-call room. While many Meredith and Derek fans were ecstatic to see that their favorite couple was on the verge of reuniting, they didn’t like the thought of Addison getting hurt. Considering that Derek knew how it felt to be cheated on, many did think that this wouldn’t be a path he would go down. It was just a bit hypocritical, considering everything they had been through.

8Owen Hunt On Cristina Yang

Owen Had A One-Night Stand With A Random Woman

Owen proclaimed his love for Cristina more than once, and he did indeed love her, choosing her over Teddy – whom he had always had feelings for. Like many of the relationships in Grey’s Anatomy that seemed like they were heading down a successful path, however, theirs faced roadblocks. When Cristina decided not to have children and then had an abortion, the latter decided to hurt her by cheating. Owen got drunk and hooked up with a friend of a patient for a one-night stand.

Later, to his credit, he admitted what he did and had a long, traumatizing conversation about his unfaithfulness with Cristina. Seeing that Owen and Cristina had been the second lead pair for a long time on the show, Owen’s indiscretion was indeed disheartening for fans of the pairing. However, she slept with him again and forgave him, but the two were not meant to be. The good news is that their honesty about their problems allowed them to remain close friends until Cristina finally left the country.

7Ellis Grey On Thatcher Grey

Ellis Had A Long Affair With Richard Webber

One major case of infidelity happened before the series started but continued to have a big impact throughout the run of the show. Meredith’s mom, Ellis, had a long-drawn-out affair with Richard Webber, even though she was married to Thatcher Grey. Ellis and Richard were in love, but their relationship destroyed Meredith’s childhood. It also severed Meredith’s relationship with her mother, who attempted suicide in front of her daughter.

Moreover, Maggie Pierce turned out to be Ellis and Richard’s daughter. Although the revelation shocked everyone, it was nice for fans to see Meredith discover she had more family after losing so many family members. On a side note, her affair also ruined Meredith’s relationship with her biological father, Thatcher, who left the family completely when he learned Ellis was cheating. By shutting out his daughter as well, this one act of infidelity did more damage to Meredith than anyone else involved.

6Richard Webber On Adele

Richard Cheated With Ellis Grey

If Ellis cheated on Thatcher, then naturally, Richard cheated on Adele, too. While the two did seem happy together, it wasn’t long before the viewers could see how much Richard’s infidelity had hurt Adele since she later accused Bailey of having an affair with her husband because he was spending a lot of nights at the hospital. Considering how sweet and kind Adele was, fans hated to see her hurting. Of course, this happened before the show’s story started, so fans never saw it in action.

Luckily, the two managed to repair their relationship in the end, but there was a time when some fans believed that Adele deserved better. Ellis and Thatcher ruined their marriage due to cheating, and it severed their relationship with their daughter, Meredith. Richard was lucky because he was able to save his marriage to Adele and stop cheating, and he became a better man as a result. However, as mentioned, Adele never forgot it, and it shows how cheating can cause long-term struggles in a marriage.

5Arizona Robbins On Callie Torres

Arizona Cheated With Lauren

Callie and Arizona were a lovely couple, and fans rooted for them through all the ups and downs. From Callie’s accident while she was pregnant to Arizona having her leg amputated after the devastating plane crash, these two had indeed been through a lot. That leg amputation, though, almost ruined their relationship as Arizona felt that Callie making the decision ruined her career and her life. They seemed to work through this, but it became part of the cause of their later struggles.

What didn’t make sense was Arizona cheating on Callie with the craniofacial surgeon Lauren Boswell. While Arizona did struggle in the aftermath of the plane crash, some fans couldn’t understand what made her cheat. Lauren came in and started flirting with Arizona instantly, and even though she knew she was married to Callie, it didn’t stop her. When Arizona cheated, Callie figured it out and split up with her wife. It devastated fans that this well-loved couple split up and couldn’t make it work in the end.

4Teddy Altman On Owen Hunt

Teddy Cheated With Tom Koracick

Another cheating scandal that occurred in Grey-Sloan was Teddy cheating on Owen with Tom Koracick. The usually cool-headed, rational Teddy suddenly decided to throw all caution to the wind when she began a physical relationship with Tom, whom she was casually hooking up with before Owen proposed to her. What was even worse was that Teddy was pregnant with Owen’s baby, and she still started cheating on him with Tom, carrying on the affair behind his back.

Teddy’s uncharacteristic behavior did have fans confused – especially since she didn’t have any intention of rekindling her relationship with Tom and still wanted to marry Owen. While fans understood that Teddy was confused, they just thought it was a little unfair that she wasn’t being honest and giving Tom false hope. She even said cruel things, such as the fact that Tom would be a better father than Owen. This was a terrible situation for Owen, Tom, and Teddy. Everyone involved in this situation deserved better.

3Alex Karev On Jo Wilson

Alex Left Jo For Izzie

With news that Justin Chambers was departing Grey’s Anatomy in season 16, many fans had begun to speculate how the writers would close his story. However, out of all the outcomes and theories they came up with, no one would have predicted what the writers came up with. It turns out that Alex had left and was moving to Kansas to be with Izzie and his children. While many Alex and Izzie fans rejoiced at the news, there was a large backlash from the other part of the community as they thought it was out of character and not fitting.

This was mainly due to the fact that Alex was married to Jo, and they had been building a future together. Even through their issues, Alex and Jo never gave up on their relationship because they really did bring out the best in one another. Therefore, for him to just leave Jo and outright avoid her made no sense and ultimately undermined Alex’s character development. It also made little sense since Izzie left Alex without a word, and he knows how much it hurts. Then, he did the same thing to Jo.

2Derek Shepherd On Meredith Grey

Derek Cheated With Renee (With A Kiss)

Arguably one of the worst betrayals on Grey’s Anatomy was Derek’s moment with his research fellow, Renee. In seasons 10 and 11, Meredith’s dream relationship with Derek went through a rough patch as the latter left for DC. Despite the many instances of infidelity in the series, no one expected Derek to cheat on Meredith. Meredith feared the worst, and she was almost right, for Derek did end up kissing Renee – although it’s possible this kiss opened his eyes and drove away any confusion he might have had.

He did come running back to Seattle, but for those who loved the relationship, his little moment with his Research Fellow was devastating. Of course, Derek did fall for Meredith while he was still married to Addison, but to see him cheat on Meredith was not welcomed by fans. For so long, they were the central couple of the series. While it was just a kiss, it was close enough, and it could have ruined the best relationship the show ever saw. Luckily, the two were able to make things work in the end.

1George O’Malley On Callie Torres

George Cheated With Izzie

George was goofy, adorable, and good through and through, so his sudden decision to cheat on Callie and sleep with Izzie seemed bizarre. True, he and Callie weren’t exactly the perfect couple, but that didn’t seem to justify the story arc where he acted on his impulses with Izzie – especially since they hadn’t really expressed an attraction to one another. George and Izzie had always been friends and never hinted at anything more than that.

The fact that Callie was also quite likable made this storyline all the more frustrating.

In fact, in his early days on the series, George had a crush on Meredith instead, and Izzie connected with Alex. The decision to pair them up seemed to come out of nowhere. The fact that Callie was also quite likable made this storyline all the more frustrating. While Derek cheating on Meredith might have been the most heartbreaking infidelity in Grey’s Anatomy for fans, George cheating on Callie was the one that made the least amount of sense, and it ended his marriage to Callie.