Re: about to end celibate period
You have gone through so much that I would suggest you wait until you are 100% ready. I have body image issues myself, and being naked in front of someone is difficult especially without some liquid courage, so I know how you feel.
I have a couple of suggestions. One would be to talk to your partner about it. You are both adults and if he really cares about you, then he will understand and not pressure you and wait as long as you want to. I know that seems a bit cheesey and cliche, but it is the truth. Through experience, a lot of guys will only tell you what you want to hear or do things they think will make you happy just to get you to sleep with them, and if he is not that kind of guy, then he will wait. He might even suggest that you wait until your are completely ready.
My other suggestion, and it might sound a little bad, would be to watch pornos. That is how I "build up" my confidence. I watch them to learn new tricks or positions. There are many different types out there, and not all of them are nasty. There are actually female porno producers that make videos for women. That might be something to look in to if you are needing help with making sure you satisfy your partner. You don't have to watch them with him or tell him that you watch them.
I hope this helps and good luck!