@cynmart5,
If I were to talk to your ex, I would say the same thing that I am saying to you. He is going to have to accept the reality that he needs to deal with you for the next 13 years. I would tell him that he should talk to a lawyer, but that also he should realize that if he does't compromise with you, it is going to be much worse for him, and for you and for your son.
I would tell your ex, were I speaking to him, that he should work to compromise with you. I would point out that in spite of all the ways he feels you hurt him, that he and you are the adults and that someone has to start acting responsibly and compromise.
I am not talking to him, so I the only person I have to say this to is you (actually both of you should start acting responsibly and compromise).
The typical outcome in custody cases is that one parent gets custody, and the other parent gets visitation rights and pays child support. Yes, in parenting agreements you have to accept that some parts aren't enforceable (although some are). That's life and all you can do is hold up your end of the bargain and hope.
If you can work this out responsibly, without the nasty fight in court, it will be better for everyone (and save money). If can't work it out responsibility and go through the nasty fight, you might end up in the same place anyway at the order of a judge (except you and your ex and your son will all have less money).
I get that you wish you never had a kid with this jerk. But, you did. And, now you have to do what is best for your kid. You can't avoid the fact that this father has the right to have a connection with his kid. You can do your best to compromise and do what you can to make the situation better.
Did you see me write that you should have a lawyer? A good lawyer will protect your legal issues and suggest ways that you can compromise with your ex at the same time you protect your own rights and the needs of your child.