coming out help!

hey guys. I don't know what to do, and any advice would be well taken. I am 15 (young ik) and my boyfriend and i have been dating for 6 months. I have felt weird in maybe the last 2 months when we'd do anything romantic/sexual and I figured out I was asexual about 2 weeks ago. I came out to him today over FaceTime, and he was completely supportive but very sad. He started crying and is really unhappy. I feel awful and I know I shouldn't because this is who I am. What should I do?