Your "marriage" is built on a lie. He's trying to love you, but he's not able to reconcile these things in his head. You can try counseling, but tbh, I'm not sure it will work in the long run.

It's not his kid. You lied to him. No wonder he's jealous. Only a few approve of your union and fewer will be willing to help you

This isn't "jealous of your ex", this a situation he feels forced into. Ya'll need therapy. Even if/when you split apart, you both still need therapy.

Your family was right, this was a horrible idea. Cry about it tonight, but start fixing this shit tomorrow. Talk to your family and ask for some help. Listen. You might be able to salvage something