Overall, you're saying you have no options, and he is withdrawn in a way that seems like he has given up. In short, you've both apparently reached what seem like different stuck points. When at a stuck point, anything that can be done to shake things up (except fighting) is better than staying at the stuck point. He won't talk to you about any options to your life as it is right now?
You answered the question as you feel has have no fear of loosing you but if you put that fear in him he will change 180. Hes bacily used to being with you in a routine situation and needs a wake up call.
I was the same as your husband and my wife said enough is enough and booked a ticket to visit her family in south america for 2 months. Being alone that long bothered me so i changed out of fear of loosing her.
I would suggest backing away and make him miss you. Hes just being comfortable with his life style and taking you for granted. If you have a famitly in a nother state, maybe book a ticket your self.
He either sounds depressed or like he has simply given up. I don't know why. Maybe he feels like this (living with you, having a child) is not really what he wanted after all. Have you asked him this? Or is the entire conversation simply about whether he will come back to bed? That (not being in bed with you) is a signal, not the problem. I don't get that he is cheating, I get that he is emotionally not there.