Dont get on with partners family.... help!?

I am from a middle cl family who's parents live in a lovely house, go on nice holiday's etc etc . My partners family are working cl and are bitter towards me and rude to my family. His family have spoilt a birthday party, weddings etc on my side by snide comments and plain rudeness. I have stood up for myself but then they all gang up on me and make me out to be awful. It have a little girl with my partner and they ensure that everytime we are at a family function she is taken away from me and my side of the family to be circulated around them. I have gone to endless trouble to accomodate his family but all I get is rudeness and it appears they are jealous. I dont know where to turn. I love my partner, but I dont see why i should put up with this. I stick up for myself and get shouted at by his family. I used to tollerate and be polite until it got out of hand. I dont want to split from my partner and leave my little girl without a father. They are not going to affect my daughter in this way. Any ideas on how to handle them?