Its all my fault

Last night I went through my boyfriend's phone while he was sleep. I found him talking to multiple girls on social media and I became upset. I woke him up and confronted him. I'm so tired of being stupid going back everytime he cheat on me. I just feel like he's the only man that I want since we have a son together. So back to last night I threw his car keys the ditch while it was raining, which I know I shouldn't have and I was wrong. He got very angry when we couldn't find it and punched me in my face 3 times leaving me with bruises, and knots on my head. I was in a lot of pain and couldn't sleep, now I just feel numb. I know it's a toxic relationship. I wouldn't dare place the blame on just him when I know I have toxic traits as well. But I know I have to leave because our son doesn't deserve to go through this.