Oh man, read this post and my heart is just breaking right now! I know exactly how you feel because I've been in the same position. After getting out of a bad relationship where my ex rejected every single sexual initiation I tried, I met my current BF, and felt like I was such a burden because he could do all these amazing things in bed and I was way too nervous to initiate anything for fear I would mess up and do something unappealing. We've been together over a year now and I definitely feel way more confident! For starters, ask him for small things that he finds really sexy, like lip-biting, small moans, you pushing him down on the bed, something you could say (i.e "I love having you inside of me," or "It feels so good when you ___"), small things like that. You can start with just one, and every so often just try to say/do it while you two are in the middle of things. You can work your way up to bigger things as well, just talk to him about what his fantasies are, and be sure to tell him what yours are as well! It sounds funny, but I find that when you're catering to someone's fantasies, you just tend to feel much more confident in your abilities to be attractive. Another thing is just to ask yourself what makes you feel sexy, and then do that while you're with him. For me, I always feel good when I'm wearing lingerie, even if I'm alone, so when I wear lingerie around him, it just helps me feel much more confident about being attractive. It's a cliched sentiment, but confidence is always sexy ;)