This guy is a predator. He is depending on your insecurity and your willingness to allow him to treat you poorly as a result of said insecurity. Get away from him. I'm sure there are aspects of him that seem wonderful. But if he's abusive in any way, the bad outweighs the good, period. I know because I've been there (however, I didn't have children, though he certainly did). You have a young daughter who is going to learn everything about relationships through watching you. So just think: would you want your daughter, when she grows up, to maintain a relationship with a man who has hit her and is cheating on her? I don't think you would. Please, get out of this relationship and get away from this man. If you do not, I can guarantee you that he will keep doing the same things to you over and over again, and, as much as I hate repeating cliches, you really do deserve SO much better.