would I be wrong for this

I'm 18 and my ex is 19, we have a 2 year old son together. Recently I've honestly just been wanting to kick him completely out of mine and my child's life. He hasn't seen our son in about two months now, and hasn't helped with him at all financially since January. I don't want him on child support or anything I honestly just want him out of our lives (at least until my son is old enough to decide if he wants to see his father or not) I have several reasons for wanting him away though. He just pops up whenever he feels like it, doesn't help financially, and ever since he got a gf he's basically forgotten about our kid. I've tried talking to him about all of this but he comes up with excuse after excuse. We broke up a year ago and the reason why was he was physically and emotionally anusice towards me and even held a shot gun at me while our child was six months old because we were in a very heated argument and I was trying to remove myself and child from the situation. I never told the cops or anybody what happened because I was ashamed that I let myself get in that position. He's also very manipulative and threatens to try to take my son if I keep him a way (which I know he really won't but it still scares me) so I just keep letting him come in and out of his life whenever which isn't good. Honestly I don't care anymore, I want him gone. He's not on the birth certificate or anything important (my son even has my last name) so if he did try taking me to court he would have to pay $300 for a DNA test and other stuff which he will not do. I just don't know what I should do though. So many people have told me I should've kicked him out of our life a long time ago but others tell me I'd be shitty if I did that. I'm lost.🤦🏻‍♀️ I just don't want my son hating me later on.