Both of you are possessive of each other and self-centered and otherwise oblivious to the other person's needs. That's pretty normal tbh. It takes a few years of talking and hashing things out to get past that stage. Counciling is always a good idea. From what the guy said, I don't see anything abusive, only petty. From what the girl said, she just wanted what she wanted without really acknowledging the emotional consequences of an open relationship.

What should have happened was true separation while girl figured things out. Now there's a baby and, if she's responsible, that puts a full stop on exploring her sexuality. So long as she loves guy, (which staying with him despite being with someone else strongly implies,) there's little to no reason to break up the family dynamic and financial stability for the baby.

There are no psychopaths or abusers here, just 2 people figuring out love is difficult to navigate.