+100 on what they all said.
There is no time like the present. You have made the decision. There is no better time. It will not be easier.
There is no "fault". you don't have to "prove" anything.
You go get a lawyer, put the WHOLE retainer on a credit card. The entire thing. If the lawyer doesn't take cards, go the bank and get a cash advance on the entire amount. It doesn't matter. It will all work out in the end. He will be splitting your lawyer fees 50/50. Just like the equity in the house, when it sells. And the lawyer can help you legally force him OUT. NOW.
Don't fret the details. I can tell you I sweated out the details, made exit strategies one after another. 20 years later I was still trying to figure out when and how.
Here is the when and how: When: NOW. How: Go lawyer up. That is the way it is done.
don't think it through too much. You've already done that, and come to the only reasonable conclusion. You know he will lie, manipulate, exaggerate and do what he darn well wants to, regardless of your desires. So, you should do what you darn well want to.