I'm going to leave my boyfriend after he got belligerently drunk and pissed in the floor
That really sucks. What the heck did he do that for?
He doesn't listen to what I say and he acts like he knows everything
I think you're well within your rights to leave this guy.  He sounds like a trainwreck and you'd be better of without him.  I hope you find someone who treats you better!
Even though I should leave, I'm not going to. I'll think about talking to him
It is completely fine to leave someone who does things like this. If you want to talk to him about the situation first than i guess you do owe that to him. Maybe this was just a one time thing.