A boundary is not a boundary if you're OK with its crossing once or twice. It's like telling your kids "Ok now, I'm going to get REALLY mad if I have to tell you this again!" and then they take you seriously on the third time. Any parent can get them to take you seriously on the FIRST try, if that's your parental expectation of your child.
I don't mean to treat your husband like a child, but a boundary is a boundary. Only you know where to draw them, but I would draw them in such a place where crossing them even ONCE brings a negative consequence.
