How to leave

You're child would be better off seeing you in a genuinely happy relationship later on than a loveless one now. Do what's best for you and baby! The father will always be around, no matter if you're together or not so don't stay together just for that reason. 

My mother in law told me to never stay with someone just because you have a kid with them. Be yourself & be happy. Tell him straight up, if he doesn't get his act together, you're leaving. Plain & simple.