How about
"Pack your bags and get out you cocklodging, freeloading piece of shit"? No?
Honestly you CANNOT trust him - every month there'll be an excuse 'I'll make it up next month' even if you get a supposed agreement from him to pay more.
YOU and YOUR KIDS are going to HAVE to go WITHOUT to fund HIS LIFESTYLE!
I beg of you get rid of this selfish waste of skin!
He doesn't care for you or your kids you're just a meal ticket.
PLEASE call and speak to women's aid or similar.
To be perfectly honest, I would never have allowed anyone to move on without FULL discussion on money, chores, ground rules.
But IF I found myself in that situation I'd black bag all his stuff, fling it out the door and lock him out!
Get him gone, NOBODY deserves treatment like this and your kids certainly don't deserve to see you treated like this OR miss out because you are essentially paying off his debts for him!
Do you want your kids ending up in the same position as adults? Because if you allow this you're teaching them they're not worth consideration or money for their needs.