Help Me I'm Curious

I'm 18 years old and i found out i had Hep C about 8 months ago when i got locked up. I haven't been with anyone since then except for my b/f now. We've been intimate twice and i just told him tonight that i have it. I feel really bad that i didn't tell him before we had sex, but i was just scared. He completley understands, but he is still curious about how he could possibly get it through sex. I've read the articles about how it's not common but it can happen. Well how can it happen? I want like an actual percentage or something that i can tell him. We use condoms and will continue to, but can i still give it to him. I don't have multiple partners and neither does he, he's the only one i'm going to be with. Just please someone answer these questions for me. Give me something i can tell him, to reasure him that it will be okay. Thank you for any help and any light that you could shed on this for me. Like i said i was locked up when i found out and they gave me no chance to research it and really told me nothing about it. I just recently got out and i hardly know anything about this disease. I just know i'm not ready to lose my b/f over it, he means to much to me.

Thank you so much for your help.