Going back(if it’s safe) is the realistic option in my opinion. He had an actual life there, where people respected him for his abilities. Here he's just a dwarf who's the WIFE of the future king. I sure wouldn’t wanna live that kind of life. Buuuut this is fiction and eventually he's gonna decide to stay in the titan's world forever. T_T
She's thriving so much and I'm loving it but all I can see is Alphonse smiling frequently. It's warming my heart UwU