OK, now you've got ME all over the place on this thing. Now I realize my previous advice will give him just exactly wants--total freedom to do what he wants and a booty call at home if he strikes out at the bar.
He says he was at a friends. Maybe, maybe not. If he was, he was still trying to make you jealous or mad enough to leave or something.
So, go ahead and set up the spare room for him. But you are going to have to be strong about not allowing him to use you like that.
As far as who pays the mortgage and who gets the house, that doesn't happen until the divorce is final, unless you want it to. Who's to say what you can afford with all the alimony he's going to have to pay you?? (for the sake of argument). Don't take his version of the future as the gospel.
You don't move out of that house unless there's a sherriff's deputy at the door with a court order.