I'm thinking of leaving because my girlfriends parents are becoming the reason why I really want to leave
Do you think that you are letting them do too much?
Yes, I'm too nice to her parents. It's because of them that I want to leave now
I think that you should keep trying with them. It will be better for your relationship in the long run if you are able to get along with her parents.
Okay, I will try harder. But if this doesn't work I am leaving.
You've done a lot so far and it would be tragic to let it all go to waste. I believe if they see how hard you're trying eventually they will be less of an issue for you.