Kate Walsh as Addison Forbes Montgomery
Dr. Addison Forbes Montgomery (formerly Dr. Addison Montgomery-Shepherd) is a neo-natal surgeon and a certified OB-GYN. Her affair with Mark Sloan provoked her husband of eleven years, Derek Shepherd, to leave her and move to Seattle. Due to work related issues, she went to Seattle and crossed paths with Derek and found out about her estranged husband's affair with Meredith Grey. Eventually, the couple ended up getting a divorce which resulted to the dropping of "Shepherd" from her last name.
Although she was very much in love with Derek, Addison gave in to the temptation of sleeping with Mark because Derek was too focused on his career. She tried hard to persuade Derek not to leave her, but her act was considered unforgivable. When she became a resident at Seattle Grace, her presence seemed to rattle Derek, and even though he was quite satisfied and happy with his relationship with Meredith, he tried to work things out with Addison. They went back to couple’s therapy, but Addison could see that Derek was still very much affected by Meredith. She gave up trying to steer Derek away from Meredith, and eventually warmed up to her. When Derek and Meredith became friends, Addison further opened up to Meredith, and even offered her a cup of hot chocolate before and after each surgery they performed together. Ultimately, Addison faced reality and finally decided to finalize her and Derek’s divorce.
The true extent of Addison’s relationship with Mark Sloan was not immediately apparent to Derek and the others, until she told Derek that it wasn’t just a one-night-stand. After Derek left for Seattle, Addison moved in with Mark, and eventually got pregnant. She immediately terminated the pregnancy, and shortly thereafter, she found out that Mark had been unfaithful to her. Addison and Mark reunited when, on one drunken night, she asked Mark to come to Seattle. When her marriage to Derek truly reached its end, she told Mark to return to New York, but Mark confessed that he was still in love with her. When Meredith was revived after having drowned, Addison felt a bit envious of Derek’s obvious adoration of Meredith. Her envy prompted Mark to insist on reviving their relationship again, to which Addison responds with a “No Sex” policy for 60 days.
Another significant relationship for Addison was with intern Dr. Alex Karev. When one of Addison’s patients asked her to perform an operation that would render her unable to have kids, Addison obliged without telling the woman’s husband. Alex knew about the incident and subtly informed the husband, who immediately questioned the Chief of the hospital. Addison tried to convince the woman to confess to her husband, but she refused. As payback, Addison decided to keep Alex under her strict supervision, something that Alex was extremely unhappy about. However, things between them took a totally different turn when she and Alex shared a romantic kiss at Joe’s Bar. Following the intimate moment and what could have transpired from it, Alex broke up with Addison, but she has kept pursuing him since.
(Photo courtesy of ABC)