You need to have a sit down with Dad first. If he isn't going to stand with you on the reasonable things, believe me, it will never work. I know, I'm there, and the kiddos don't even live with him. (In fact, saving $$ to get out now, at least I haven't married him and have to figure out divorce issues as well.) Make a list to discuss with him first and ask for his thoughts. Be direct and reasonable. They can clean up after themselves, and show respect. But if he isn't going to stand beside you, bail now before you end up miserable. Stand your ground, because if you give in, none of them, Dad included, will ever respect you.