How do you know if you are depressed or not? Fighting with your partner will always make you feel bad.
And, believe me, in laws I called outlaws when I had them. My ex insisted we see them every week and I hated them. But she sulked something terrible if we didn't go, so I went, and took the kids.
My family lived interstate so we didn't have to go see them but I did go visit them on holidays, with her and the kids, once a year.
You and your partner need to talk this out. And let each other have a full say before you make a decision.
I;m thinking the outlaws should be visited by their son or your parents by you. Do it on the same day so you can't be in twoplaces at once. Equal time. Or, more simply ask him if you and he are a family or is he still only in his parents family. Marriage is a familt and must be respected as such.