I'm not psychic Capes, (if I had have been my life would have been a lot less wretched !) but I have read "The abusive Dickhead manual for lonely downtrodden mothers",
Step by step, he will follow the script.
So, Did you start the benefits? If you don't & he decides his next card to play is to keep his salary, you will be financially in difficulty & then your resolve will falter. also at this point you can ignore him, but it will not be the case when you can't pay the rent/elec/nappies etc.
You say you have some savings, but what happens when they are used up?
He knows he has the upper hand re money, you can wait now for him to start using it. & he will.
He has contacted you because he is sitting alone in his mother's house/other on a Saturday am, & has nothing to do.... It may not be as pleasant as all that, his Mother, may be telling him to sort it out, or get a flat, or enquiring just how long he is staying...She/They may not condone either, his going out all night, every night, & lazing around on the w/e !
he may also have been putting on a show for her/them & showing more decent behaviour, he may be missing his Poker nights, & getting weary of being a (fake) reasonable person !
You will have to provide him with access to kids (have they even mentioned he is not around yet?) If he says he has rights, you say yes you do, your children are keen to go out, you can collect them at X, & return them at X...
You do not need to talk to him. You have detached, so don't listen to his golden lies, promises, memories of good times, presents, off of marriage,
He had ample time to cherish you. He didn't.
Totally amazed you painted the play room ! Awesome !