Credit: Katie Yu/ABC

Season 3 of Once Upon a Time ended without ever addressing the fact that Rumple (Robert Carlyle) killed Zelena (Rebecca Mader), going against now-wife Belle’s (Emilie de Ravin) request. Now that the couple has tied the knot and is seemingly living their happily ever after (finally), could their relationship come crashing down in Season 4 when (and if) she finds out about his recent actions?

“Rumple, as he's told us, is a difficult man to love,” co-creator Eddy Kitsis tells TV Guide. “He's clearly up to something. As we've said before, his love for her and those vows were genuine. He's also the same man who promised her he wouldn't kill Regina (Lana Parrilla) and then found a loophole with the wraith. She's definitely going to be upset when she finds out. It's a matter of when and how.”

Yikes! From the sound of things Belle will definitely be finding out that her hubby has betrayed her trust (again) — and we suspect it will cause a lot of friction for the newlyweds. We don’t think they’d divorce over this, but it could put Rumple in the metaphorical doghouse for a while. Good thing we know he has it in him to prove he’s a good man.

“Last year, what we loved is that Rumple finally broke the cycle of bad dads from his family and sacrificed himself, and then Neal (Michael Raymond-James) brought him back from the dead,” Eddy continued. “We didn't really get to explore what is going on in his head because he was held a prisoner by the Wicked Witch, so we really want to focus on Season 4 and get in depth into what he's thinking. What is it like to lose your son? To die and come back to life? What is it like to marry the person? What is it like when you get what is supposed to be your happy ending?”

Geez, it sounds like Season 4 is going to be quite the visit to the shrink for Rumple!

What do you think will happen when Belle finds out Rumple killed Zelena? Will she ever forgive him? Hit the comments and sound off!

Carson Blackwelder is an Associate Editor at Wetpaint Entertainment. Follow him on Twitter and Google+!