New BF doesn’t know I’m pregnant

Well the title pretty much says it all, I’m 2 months pregnant I met this guy while I was dealing with my babies father (My ex now). We just started having sex last week and he has no idea that I’m pregnant with my exes baby. When do you guys think I should tell him?

He’s a really nice guy and I really do wanna be with him. But he also like rough sex and I can’t have him harming the baby.