I think the girls pretty much covered it here... but I do have a few thoughts.
Have you tried to seek counseling since you've started losing weight? If you've read anything I've posted you know that on this journey I started seeing a therapist. One of the BEST decisions I ever made. While we're focusing primarily on my binging disorder right now, there have been discussions about how eventually there are things that will be brought up BECAUSE of the weight loss and getting to goal. Meaning you don't have something to hide behind anymore and there are body image issues you have to work through as well.
NO ONE IS PERFECT. Unfortuantely in this society we've been beaten over the head with the "model" perfect image which doesn't really exist because even the models that are 5'10'' 100lbs have things airbrushed.
YOU have to be comfortable with YOU... YOU have to be able to make YOURSELF happy before you can make your boyfriend happy.
Being comfortable in your own skin is something we ALL struggle with on a day to day basis. Like someone else mentioned... make a list, for every one thing that you find FLAWED find something at least two things to LOVE about it. Make a list of affirmations and say them to yourself EVERY DAY. You feel like a huge dork at first but eventually it starts to sink in. You and your boyfriend started dating PRE-weight loss, correct? Your boyfriend LOVES you for WHO YOU ARE.... and let's face it... he's ATTRACTED to you. All of those flaws you see, he doesn't. Isn't that one of the best things about a relationship? The other person sees things in you that you don't? When it comes to intimacy... start slow if you need to. Like someone said, holding hands, hugging, maybe snuggling.... I personally don't like it when someone touches my stomach... it makes me SUPER self conscious... so there are ground rules of "don't do that, please." It's not really as big of a deal as you think it would be.
And I'm just going to back up what someone else pointed out... it's great that you can recognize the problem, but remember, you are a TEAM (or should be) so you have to find the SOLUTION together.
I'll be the one to burst your bubble (please don't hate me). You are 19. Boys will come, boys will go.... I remember meeting an ex that I seriously thought I was going to marry.... he was the first person I ever REALLY fell in love with (I also happened to be 19 at the time).... that was 7 years ago. He's married with a kid now... and NOT married to me (thank god). I have been blessed enough to love many people and in very different ways. I have been IN LOVE... like seriously head over heels on more than one occasion. Those didn't work out.... One relationship took me 2 years to get over. Guess what? I got over it... and just when I thought NOTHING would touch the way we felt about each other or the connection we had with each other and that I would NEVER EVER feel that way about someone ever again.... someone else showed up unexpectedly. I'm not saying that this guy isn't the one you're going to marry.... or that you don't love him or don't know what love is, I'm just saying... we get caught up in what we THINK things should be, but sometimes it's now whats in the cards.
Focus on YOU and everything else will fall into place. Remember that a relationship is about PICKING AND CHOOSING your battles (some just aren't worth the battle) and about COMPROMISE and COMMUNICATION.
Hope that helps.