Problems with a relationship

I’ve been in the relationship for almost 6 months but I’ve known him a long time. Which is why I ended up telling him that I was molested when I was a young kid by my moms boyfriend. Well we just started to become more sexual and I’m having a really hard time with it. He’s the only one I’ve ever done anything with and he’s also the only one that knows. I feel bad when I freak out oh him. Bc he doesn’t know what he’s doing wrong. How do I help him understand?