Remember that trying to "talk" to someone so invested in exploiting you, who doesn't like you, who has resented you for years, who is so determined to use you, will not be easy.
He will probably be angry, abusive, upset, even cry and threaten to self harm, ...........ANYTHING, to get you back in your box accepting the status quo.
He is so far ahead of you and always has been.
You were spun a tale from the beginning, shown a completely false few of him.
He was so into you and spending time together.
Now he can't bear to even bring you a coffee such is his resentment.
He's a gamer.
He was ALWAYS a gamer.
He just hid that side of him.
You were sold a false facade.
Of course he isn't a monster.
It would be much clearer if he was.
But he is living off you, in your home, resenting your child in HIS home.
I agree that because of your abusive past you were primed for an abusive coercive relationship.
I think you would benefit from talking to Women's aid.
You are spending money on his Ex that should be put away for your childs future.
I know this is overwhelming but this is so far beyond his feral children taking over and thrashing your house, ...........though it definitely indicates how little he likes and respects you, that YOU pay to have YOUR house cleaned after his children thrash your house.
This is the environment your son is absorbing.
He deserves better.
You both do.
Oh and the idea that his children might move out, may never happen.
They live for free.
He's not going to pay for university.
How will they afford that?
Will their mother want 3 adult children that may or may not hold down jobs, living full-time with her?
You are possibly being primed for the long haul with the way housing is going.
He is well capable of making a claim after so many years which could result in YOU having to pay out money to him after years of him living in your house for free.
I keep repeating, he is so so far ahead of you.
You so need to wake up to how you no idea what is going on with him.
You do know that he resents you, doesn't want to spend time with you, resents your son, feels he shouldn't contribute rent.
Why is it so hard to believe that he has long term plans to bleed you dry.
All the time your house is thrashed.