Grey's creator Shonda Rhimes teases the bizarre love triangle in an interview with TVLine, saying that Mer won't be the most welcome of third wheels in Season 11: "Jo is going to be horrified to discover how much time Alex is going to be spending with Meredith and how much time Meredith is going to be spending [at their] house."
So why is Mer monopolizing Alex? Shonda explains that Alex feels responsible for Mer now that they're the only two of the "M.A.G.I.C." group of original interns — as if Cristina (Sandra Oh) handed Mer off to him at the same time she left him her seat on the hospital board.
"The two people she talked to before — her husband and her best friend — are now not available to her," Shonda observes. "So she's looking for someone to talk to. And Alex finds himself in the uncomfortable position of being the recipient of a lot of the stuff that Cristina would have been left listening to — sometimes in very funny ways."
We can just picture it now: Alex telling Mer, "Dude, I'm not your freakin' person."