Chances are you boyfriend will be thrilled and appreciative that you chose to open up to him about your disorder. It is a true honor for someone to let that secret out to their partner. I rarely show my panic attacks and anxiety to my BF, but he thanks me when I call or go to him for comfort. Before I was open about my struggles he at one point complained that I did not let him into how I felt, he didn't like that I was being secretive and possibly not trusting of him.

Every one has issues and the perfect relationship is when these can be worked on together. He's not going to hate you because he discovered this 'new side.' You're not 'damaged', he already find you perfect. You are the same person. If he loves talking and hanging out with you, he already fell in love with a BDD girl and it's not like he's gonna fall out of love. I had the same "damaged goods" fear, but revealing myself improved our relationship and I realized that even when I am depressed that never changed how he appreciated my company.

You are his girlfriend and he is going to take you seriously. He trusts you and what you have to share.