Your best bet is to dump him. People with kids are a whole different ballgame. One you didn’t sign up for and didn’t prepare to play. Do you really want to worry whether he’s ever going to get back with his ex? Do you want to share him with his daughter? He is now going to be forever torn between his family life and his dating life.
Let him go and find someone who understands the meaning of family planning. Pregnancy is a life-altering event. Don’t let someone else’s alter yours.