Kevin McKidd and Sandra Oh

It's been nearly a month since the doctors of Grey's Anatomy have graced our television screens. With so many relationships left in the air — Cristina and Owen's disagreements about the future, Stark asking April out, Jackson and Lexie hooking up — TVGuide.com has compiled a handy breakdown to catch you up on where each couple stands and what's next for them.

Meredith and Derek (Ellen Pompeo and Patrick Dempsey): The pair has been grappling with infertility issues, which will come to a head in the musical episode. "It's starting to be a really sore point," executive producer Shonda Rhimes says. "Part of this episode is about really bringing up how painful it is for Meredith to be watching other people get pregnant, have babies and deal with that other stuff. We've been using the clinical trial for a while and that's going to launch into a very big story about them as we head towards the end of the season." Don't fret though. We're hearing it may be good news.

Grey's Anatomy Boss: Infertility will become an even bigger issue for Meredith and Derek

Cristina and Owen (Sandra Oh and Kevin McKidd): While Meredith has been hoping to get pregnant, Cristina revealed to Owen that getting knocked up is not part of her life plan. "It's almost like they didn't quite check in on certain fundamental issues before they tied the knot," McKidd says. "So, a lot of that's going to come back and haunt them." Adds Rhimes: "I don't think the end of the season is going to be easy for any of our fans, but I think it's going to be pretty explosive for [the Cristina-Owen ones]."

Callie and Arizona (Sara Ramirez and Jessica Capshaw): As Arizona struggles to find her place in the tri-parenting arrangement, she and Callie will go away for the weekend, which will lead to a turning point for Callie to figure out "why her life with Arizona is worth fighting for, if that's the case," Ramirez says. "She loves them both in different ways." Rhimes adds that she has always believed the women are "MFEO... made for each other," she says. "All of the issues that fans have been feeling — that we've been feeling — about the fact that this is not Arizona's dream to have a baby with Mark Sloan, and this is not necessarily the way that she wanted any of this to happen, is going to come to a head and be a big part of the [musical episode]."  

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Mark, Lexie and Jackson (Eric Dane, Chyler Leigh and Jesse Williams): Following the announcement that Callie was pregnant with Mark's baby, Lexie found a new love interest in Jackson, whom she shared a steamy shower session with in the last episode. "It's going to upset him that she's going out with somebody else who's handsome," Dane says. While Leigh believes Lexie does still love Mark, she doesn't think Jackson is a rebound. "She can confide in him and she can talk with him," she says. "There's something refreshing about it that it's someone who is in the same place as she is, just trying to make it as a doctor. It's definitely something that has the potential to blossom into something pretty big." 

April and Stark (Sarah Drew and Peter MacNicol): When Grey's returns, the series will have jumped ahead, so April and Stark, who asked her out in the last new episode, have actually been on a few dates now. "I think she's really enjoying having some sort of companionship," Drew says. "She truly does like him and she sees something in him that he hasn't allowed anyone else to see. But you'll see that things go awry because it's not a physical relationship and then we realize he feels much more deeply for her than she does for him." And in case you're wondering, yes, April is still a virgin. "She's not losing her virginity for awhile," she says, but adds that when it does happen, "The [writers] promised me that it will be beautiful." 

First Listen: The songs of the Grey's Anatomy musical episode

Alex and Lucy (Justin Chambers and Rachael Taylor): Even though Taylor left to shoot the Charlie's Angels pilot, we hear the pair will share a smooch before she exits. "Justin seems very kissable to me, so I would be very happy to be one of the many women that his character has been with on the show," Taylor says. Lucy Fields is no random hookup either, says Chambers. "Alex still doesn't wear his heart on his sleeve," the actor says. "I'm feeling that he's really smitten with this new girl, and I don't think he's been smitten with anyone for a while."

Bailey and Eli (Chandra Wilson and Daniel Sunjata): Following a hot on-call room tryst between the new lovers, the pair will be singing with the other couples during the musical episode. "This whole season, it's been about getting on with it so that we weren't just mourning after the shooting," Wilson says. "So, she let herself begin to try some new things. That's not necessarily the 'new Bailey' but it was just enough mourning. I don't even think she's in a place where she's calling it a relationship."

Grey's Anatomy returns Thursday at 9/8c on ABC.