I feel so bad you are suffering so much, and I am here again to help.
Your husband seems way confused between dead-past memory and reality, and it impacts your marriage tremendously.
It seems to me, he is overly playing self-pity game like a child, and you are playing sorry wife role accordingly, and it makes your marriage worse as time goes by, and you guys are in worst loop without healing. That's why I suggested having a mediator or marriage counselor. It seems you have not tried for some reason. I can see you suffered enough.
You guys do not have real communication, so you guys cannot move on. Your husband's cold shoulder, silence and divorce threatening treatment will not resolve this issue at all, you have no idea how to handle it but just take it and suffer. It is bad.
You are not the problem of this marriage. He is. He is victimizing himself, baby and mostly you. Be strong, stand up for yourself, baby, and him, fight for your happy marriage. Crying over his torturing will not do anything for you.
Sit down with him today not tomorrow, look into his eyes (I always do when I need to talk sincerely), talk honest what has happened, and tell him you are willing to devote yourself to make your husband and baby for the rest of life, and let's move on together for baby VERBALLY & CLEARLY.
This is what I will say if I am in your position.
“I am sorry, but you need to stop this, and I cannot let you divorce me. You have punished me enough. I got your message VERY clearly. If I have time machine, I go back to past, lock myself in cave, and would not talk to anyone before I met you. But I cannot do it. So, I will do my best to make it up to you, and make you happy. Let's stop here. We can build the happiest marriage from here with our baby. We are supposed to be together for the rest of lives. Love me just like you promised me as husband as you promised. I will be your best wife ever. Divorce is not option. Period.”
You are the mother of his baby, and he has life long obligation to love & respect you as wife. That is what the marriage about. It is JUST SILLY & CHILDISH he is sabotaging the whole marriage due to the insignificant past, which happened long before marriage. You need to be strong for yourself and your confused husband. He needs to be reasonable.
I have to assume that dating someone is not acceptable in your culture. So as divorce. Divorce is not acceptable in your culture. He has clearly double standard, confused head, and no direction, but just having fun with the blaming game. It is just silly and useless. If he divorce you, abandon you his baby, will he find a better girl who never dated any person as his life? No way! 0% Chance. So, how silly is this? It is just NON SENSE!!
Your husband's jealousy over your past was somewhat cute, but not anymore, and getting out of control, and monstrous. Give him a sweet treatment tonight as lover (you know what I mean), and make sure he is VERY happy.
FYI.
I know men will not agree with me, but I found out that men are like just children sometimes, and need constant assurance and ego boost. :)