My ex hit me? Should I not let him see our son?

We share a 4 year old son together. We've been split up for a couple months now. Ever since our break up, he went MIA from time to time. The other day it was our son's 4th bday party. I invited him and he didn't show up which ruined my sons mood for the entire party.

The next day I went over to my ex's house to confront him. We got into a really big argument. He was hungover and kept yelling at me to leave. Which made me even more mad so I kept yelling at him more. He then told me to shut up, pushed me on the couch and choked me then busted open my lip. I ran out the house and drove off.

Now, he's calling me and apologizing to me about what happened. I'm still completely tramatized about what happened. I have no idea what to do now. He face timed our son on the IPad and asked if he wants to sleep over at his place. I told my son he couldn't go and now he's upset at me. I don't how to tell him what happened. I covered up my bruises with makeup so he can't see and I just told him I fell on the stairs and hit my mouth. But he's begging me to go but I'm just so angry and hurt right now I want to cut my ex's life out of our lives completely. What should I do? My son loves his dad so much and it would crush his entire world if I try to take his dad away from him. My ex was a great dad before the break up. I'll give him that. But recently he's been all about himself and my son is to small to see through all his excuses on why he can't see him sometimes. Ugh, what to i do?

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