My fiance and our love life?

This is very awkward to talk about, but I'm so shy during sex and even phone sex. My fiance and I have been together for a year & a half almost and he's the only one I've been with sex wise. I had an incident 4 years ago with a guy & force and since then it's even harder not to be able to get in bed with me. My main reason was I wanted to atleast be engaged before having sexual activity take place. I was so messed up I didn't even want a boyfriend, kiss or anything. I feel so bad my poor guy says he enjoys what I do attempt to do & understands about my past and lets me know it's okay and he doesn't even care if were intimate. But I mean we plan on getting married in the future, so my question is, "how do I stop being shy when it comes to being or talking sexual?" I love him so much and he's the greatest but I feel dumb! He is very good with me when it comes to intimacy or even just being a sweet, caring man. I can't even say certain things cause I'm so shy or even embarrasssed?

Please help me!!♥ ):