Justin Chambers by Bob D'Amico/ABC, Chyler Leigh and Elizabeth Reaser by Ron Tom/ABC Justin Chambers by Bob D'Amico/ABC, Chyler Leigh and Elizabeth Reaser by Ron Tom/ABC
Our series of Grey's

refreshers continues with a look at the risky love triangle of Alex, Ava and Lexie.

The Couple: Alex Karev ( Justin Chambers)/Ava ( Elizabeth Reaser)/Lexie Grey ( Chyler Leigh) Where We Were: Oh, Alex. Seriously, could you be in more of a love triangle if you tried? Granted, we're not sure if you're capable of truly being in love since you usually end up being a jerk to most of the women you're interested in. So who knew you could be such a softy with Jane Doe, who then became Ava and then became Rebecca? (But we'll just call her Ava for now.) You saved her from certain death during the ferryboat accident, laughed with her and comforted her during her painful recuperation, helped her pick out a face and name, and delivered her baby safely. But Ava's husband finally found her and took her home. So what's a lovelorn Alex to do? Hook up with the most inappropriate girl on the block, Mer's baby half-sister Lexie. When Mer found out, she freaked out twofold - about the fact that a man-whore was hooking up with her sister and the fact that she felt Lexie was trying to invade her life. But we all knew this fling with Lexie was just Alex's coping mechanism to deal with the loss of Ava. So when Ava returned to the hospital, sans husband, Alex and Ava's amazing bond and chemistry finally came to a head in the on-call room. (Where else?) Later, Ava visited Alex and begged to watch him work. She sat next to Lexie in the galley, and the two chatted until Lexie realized that Alex and Ava had hooked up. As expected, she gets royally pissed. (Triangles were never this complicated in geometry class!) Where they're headed: Lexie still finds herself drawn to Alex, even though he lied to her about Ava. When she confronted him about Ava, he said it was over and that Ava was never his girlfriend. Um-hmmm. Knowing the Grey sisters' history with inappropriate men, I'm sure Lexie will continue to see Alex until Ava returns, which you know she will. Grey's creator, Shonda Rhimes, recently told TV Guide, "Alex is going to have to be brave, too. Because things are coming to a head with the woman we know as Ava/Jane Doe/Rebecca. And when it is over, he's never going to be the same." Possible roadblocks: For Lexie, the biggest obstacle is the fact that Alex may actually be in love with Ava. Also, Alex tends to shut down when he's rejected. So if Ava ends up staying with her hubby because she fears Alex can't commit, Alex could be headed for a Defcon-style shut-down. For Ava, Alex has abandonment issues because of his abusive father and because just as he was falling for Izzie, she left him for Denny. Either way, I don't think this will end well for anyone. - Erin Fox Have more catching up to do? Use our Online Video Guide to watch full episodes of Grey's Anatomy now! And don't miss our photo gallery of Grey's Most Jaw-dropping Moments!