I started living with a guy, he has a child from a previous marriage.

The guy left his wife's apartment and everything else, and moved into my apartment (a one-bedroom in an old house).

Sometimes he takes his child to "live" with us (this was not discussed when we moved in). By the way, the child is very bad-tempered, can't wash his own clothes (he is 13).

I'm not against him hanging out with the child (I'm even for it, a father shouldn't abandon his children, and I'm not against him hanging out with his wife), I'm not against him going out with them myself, I'm not against the child coming to visit, but I don't want him to stay with us overnight, and especially not in my house: firstly, there is simply nowhere for him to go, and secondly, I am not guilty of his lack of education and basic life skills and I don't want to clean up after him! But the guy says he has to.

How can I make him understand that I don't like it?