<P> Alex helps Izzie recover from Denny's death and advances Izzie but Izzie backs away since she is still in the process of getting over her loss and they remain friends . Alex spends a period of time working under neonatal surgeon Dr. Addison Montgomery (Kate Walsh), and though he is later released to work for plastic surgeon Dr. Mark Sloan (Eric Dane), he finds his interest returning to Addison's firm . Addison is attracted to Alex, and the two share a kiss and later sleep together . In the aftermath of a ferry accident, Alex rescues a pregnant woman (Elizabeth Reaser) who awakes with amnesia, and grows close to Alex as he helps her forging an identity for herself, picking out the name Ava . After she gives birth to her daughter, Ava's memory eventually returns, although she tries to hide it from Alex as she had recently left a bad marriage . He convinces her to tell him her true identity, and she reveals herself to be Rebecca Pope . Alex turns her down after realizing she's married, feeling that he is not good enough for her . </P> <P> Rebecca returns and she and Alex sleep together before she goes back to her husband . Alex has a brief relationship with intern Lexie Grey (Chyler Leigh), but chooses to be with Rebecca when she returns and tells him she is pregnant . After Rebecca attempted suicide, Izzie convinces Alex to admit her for psychiatric help due to Rebecca's hallucinations of her pregnancy . Alex later breaks down in Izzie's arms, and the two kiss . </P> <P> Later in their relationship, Izzie begins hallucinating about Denny, and uncovers the fact she has metastatic melanoma (Stage IV) with an estimated chance of 5% survival . It is revealed that Izzie's hallucinations of Denny are, in fact, caused by her tumor . Alex is shocked by the news, but finds the strength to stay by her side . Izzie plans a wedding for Meredith and Derek, but when Derek finds Izzie has another inoperable tumor in her brain, they give the wedding to Izzie and Alex, who marry in front of all their friends . Izzie debates whether or not she should undergo a risky surgery to remove her tumor and Alex supports her, but eventually insists that she should have the surgery . Alex performs CPR on Izzie after she flatlines . </P> <P> Izzie regains a heartbeat but is soon fired leaving Alex a Dear John letter and no clue as to her whereabouts . She later returns to the hospital and says to Alex, thinking he had a hand in getting her fired, that she could not forgive him for talking to the Chief . Alex says he could not forgive her either for not giving him the benefit of the doubt and leaving without talking to him first . Alex re-kindles an old flame with Lexie . Alex seems to have recently found that his calling is actually Peds and not Plastics as he had decided in the earlier seasons . Seeing Alex's ability to handle child patients, Dr. Arizona Robbins shows an interest in mentoring him for that specialization . Alex's brother Aaron comes to Seattle Grace for surgery, and lots of painful memories resurface because of this . Meredith discovers Alex, along with Aaron and their sister Amber, had been in foster care for five years when their mother could not take care of them . Alex is also served with divorce papers from Izzie . Alex is shot in the hospital by a deceased patient's husband, but survives with the help of Lexie and Mark . While undergoing treatment, he mistakes Lexie for Izzie . </P>

Who does alex marry on grey's anatomy