J.,
Not sure what advice I can offer, but your husband needs to think about the amount of stress he is putting on his child. When my son's father and I began trying to mend our relationship, we've not been together since I was 3 mos. preggers, when my son was 6 mos. old so they could bond it was tough. As time progressed, my son would through tantrums when he got older and clind to me and eventually didn't want to be around his father at all.
Our kids can feel the tension in the air, and begin to fear the person that brings on that stress. As her father, he should understand she needs a stable environment that does not include manipulation and selfish behavior. His paretns raised their children, and they are done now. He needs to stand-up to them, and whether you stay together or not create ground rules for how they should treat you and his child.
My relationship with my ex's parents was never good either, and really after we broke up it got worse. My son doesn't see them unless his Dad takes them over there to see them. They don't send birthday cards or anything, and it all comes down to me saying 'no' about my son being dropped off their for visits without his Dad when he was four mos. old because they didn't want me in their house.
Not sure if any of this will help, but stand your ground for your little girl. She deserves to have both of you in her life, but not at the expense of her happiness and security. If living with his family in not a healthy situation for everyone, than your child will suffer and that is never good.
If you can, sit down with your husband. Make a journal of points you want to address and express your concerns for your daughter, as she is really the most important thing. If you can put the goal of living in your own home on a timeline, so he sees their is a future goal for YOUR family together and that this is the time to be present for the family the two of you are building together...
I wish you good luck.