Unfortunately it's another one of those things you cannot control.
His cancer would have come back regardless of the house situation. It's nothing you did or did not do. You are not to blame for setting boundaries and enforcing them. He is responsible for the consequences of his actions. You are responsible for taking care of yourself and doing what you need to do to be healthy and happy.
All you can do now is give it to your HP. Pray that your HP will guide both of you down the path that was meant to be.