Croasroads

My son's bio father has been out of his life for almost 2 years. He never asks how he's doing, doesn't even bother asking if hes still alive. Part of me wants to talk to him and ask him how he could help bring a child in this world and not care for him at all. But my husband whom I love very much and loves my son as his own has been there for me and my son since day one. My son calls him daddy. Should I say something to my ex or should I just forget him?