What do I do

So I'm so beyond words but I'll try to explain I love my husband more than anything but his dad is trying to split us up for the past year and I mean withholding his income and his half of the estate and this has gotten so bad that his daughter moved in with her mom now we are fighting once a month or so because he doesn't want this to destroy me or our child (I'm 19 weeks and 5 days pregnant) I just don't know what to do I'm trying to be supportive but it really is taking a toll on not only him but me as well