Well done OP.
It is very positive that you no longer feel like such a fool.
The house needs to go on the market asap.
Remember to have a look at what you have contributed.
He deliberately moved his son in, screwing you financially.
You pay 50% of the morgage and he gets a home for him, his son and his girlfriend.
Complete CF's the lot of them.
Youf feelings of relief are going to grow and possibly your feelings of anger too.
Practice your narrative, he utterly disregarded your wishes in YOUR home.
His behaviour was completely unacceptable and you are done.
The sooner the house is sold the better.
Keep posting.
We are here for you.