Been living in for the last three years. He refused to move out, so I had to leave to be legally separated. There are no agreements that he would get the house.

The only time it would become trespass is if there were a court order barring you from the home. Either by direct order or through a restraining order. If no such orders exist and your name is on the title then you have just as much right to the home as he does till a court says different.

My only suggestion is that if it is getting this messy early on then do not enter without police escort to remove your things. Otherwise you could have a disaster on your hands.