Paternity test question. I just found out I'm pregnant.

My boyfriend doesn't want me to find out if the baby is his or not. My ex was physically abusive but died in a motorcycle accident. Yes I will admit I was sleeping with my boyfriend while I was trying to get away from my ex. My ex expected sex or he would beat me. I had just finally left him when he wrecked his bike, I have a feeling it was in a fit of rage. Since there's no one to come forth and claim the baby away from my boyfriend. Should I give him his way and not find out? Or do I need to know for health reasons?