Should I stay or should I go?

Hubby and I have been married 10 yrs. going on 11 in November. We split once for 6 months, I came back wanting to make it work. He has cheated on me several times, although I do not think he is now. I always took jhim back but the last time, I was in another state and he stayed here to sell our home, and wound up having a young woman move in to MY bedroom...behind my back.I cannot forgive him this time.We have tried so many times. We are back to sleeping in our own rooms and hardly have any interaction as he now works Overnights.We have a 7 yr. old child in the house, not his or mine, a grand, who really used to love his grandfather, but says now he is nothing but mean.His family is under the impression that everything is fine behind closed doors, while my family knows I am NOT happy,and neither is HE.We argue and scream at each other every time we are in the same room, and I do not want my grandson growing up in this atmosphere. I think I need to leave, however I am disabled and cannot support myself financially. I don't want to stay for financial reasons but he IS my legal husband, and it is his responsibility to support me, but I am not a USER either.I want to leave or I want him to leave...we just can't g on like this.