Honestly hun, the relationship needs to be let go of. If he cant make you smile, and cant treat you proper. Then purhaps youll be better off single, but still hold a friendship because lil one will need a daddy too. But however being a single mom isnt bad. My momma did it with 4. You can do anything you your mind too. Just remember dont stress as much, you and your babies health happiness is #1. :) hope you figure something out.
Then leave. I'm actually trying to understand wtf I'm going to do in a situation much like yours but we already have to kids and if you don't leave now omg will it be so much harder to when your Lil baby is attached and used to him being there all the time!