Hi Diana, I am so sorry your bf did not have the courage to be honest before moving you. And also before making a third child with you!
If he says he does not love you then there is really nothing you can do to save the relationship. Just try to keep it friendly for the sake of your children.
Smothering this guy or trying to get answers from him will frustrate you more and make him feel he cant be around you at all. I doubt that he will give you any answers that will make you feel better. I understand after 8 years it is very difficult to start a life of your own, one that will make you and your children happy. Your children will need you to make a happy home! Good luck to you