Elizabeth Henstridge and Iain deCaestecker shared their thoughts on forthcoming ups (and downs?) in FitzSimmons’ relationship on Agents of S.H.I.E.L.D. season 4.

Speaking to Hypable at San Diego Comic-Con, Elizabeth Henstridge admits that after three star-crossed seasons, her hopes for the couple are simple.

“Honestly, I’d just like them to be happy and fine for a bit!” she says. “But we’ll see. I mean, this is the first time they’ve been in a relationship romantically, and they’ve been on holiday together.”

We doubt we’re alone in hoping for some “snorkeling”-related flashbacks. But Henstridge notes that Agents of S.H.I.E.L.D. season 4 will see FitzSimmons forced to deal with the mundanities of the Marvel-heightened reality.

“Now they’re just trying to concentrate on being a romantic couple, and also trying to navigate those waters,” Henstridge says. “Because if you’ve ever been in a relationship, you know that it’s not easy, [especially] at work.”

“They live at work!” Chloe Bennett observes.

“They’re very close,” Henstridge agrees. “So it’s kind of a fun dynamic we’re going to get to see.”

According to showrunners Maurissa Tancharoen and Jed Whedon, FitzSimmons’ heightened dynamic will draw more than a little inspiration from their own marriage.

“They’re very much in a relationship,” Tancharoen says, after Whedon joked that the couple will have three children at the start of Agents of S.H.I.E.L.D. season 4. “But with that, of course, comes some new challenges. Working together, loving each other, living together… we don’t know anything about that! It’s not pulled from life in any way.”

“It’s getting easier to write the scenes, because we just write what happened last night,” Whedon says. “But usually that’s like, ‘You wanna watch something? Snore!’”

Both Henstridge and Bennett find elements of similarity between FitzSimmons’ connection and Tancharoen and Whedon’s.

“Their friendship is similar,” Bennett notes.

“Yeah, you see a lot of their personalities in them for sure, and… kind of how they play off each other,” Henstridge agrees. “I think they definitely put that in the writing for FitzSimmons. They’re a lot more solid than FitzSimmons, in terms of knowing what they want! But definitely the bond is the same.”

As for whether or not Simmons and Fitz will follow Whedon and Tancharoen’s path to becoming parents, Henstridge only laughs that “Babies would be fine!” Ming-Na also expressed glee at the idea of “Little FitzSimmonses running around!” but Iain deCaestecker is more concerned with the earlier part of that process.

In previous seasons, he observes, “They were really, like, they were very shy about talking about their feelings. Whereas now… they’ve seen each other’s genitals!”

“Now you know why we’ve moved to 10:00!” Ming-Na cackles. “For that reason alone!”

Agents of S.H.I.E.L.D. season 4 premieres on Tuesday, Sept. 20 at 10 p.m. on ABC.

What do you think ‘Agents of S.H.I.E.L.D.’ season 4 holds for FitzSimmons?