He’s a danger to you, then he’ll def be a danger to that baby. Cut ties immediately do not put him on the birth certificate, go into the hospital as a no name patient so he doesn’t know when you have your child & raise & love your baby boy the best you can. He doesn’t need to be in his life especially while threatening you while you’re pregnant with his child. Also get a restraining order.
I had an IVO that stated BD couldn’t be near me, near the hospital while I was in attendance and I had an alias name for all my appointments and L&D. I suggest you at least ask for an alias/no name and make sure he isn’t an emergency contact.
Definitely walk away for your peace and for your children! They don't need to see or hear their mom being disrespected by their father!