The lack of sex could kill my relationship

I created this account specially for this. So here's my situation...My boyfriend and I have been together for over a year now. When we met we lived in the same city and spent the first 3 months of our relationship together. Then I had to move to another city. Since then we see each other every two weeks, generally. And we talk everyday at least twice.He's a great guy has helped me a lot so far. I've grown as since we started dating. And I can say that he's the first man I've ever loved.Honestly our relationship is great... Or it would be it if wasn't for the lack of sex. It can sound minimal but it's not.We've gone 4 months without sex (during this time we still met every two weeks btw). I cant help but to feel rejected.Talking about it is not easy. Nevertheless, we've talked about it a few times. Every time it happens, it starts with me asking if he's not attracted to me, which he says he is. Then I wonder whats keeping us from having sex. So far I've never had a satisfying answer to this question.He's not very open about his emotions. The only time he's tried to explain why, he said he's had bad experiences in the past...Well back in the day, he used to only have unprotected sex and he got chlamydia once. (BEFORE SOMEOE ASKS FOR US TO GET TESTED, IT'S BEEN DONE AND WE'RE BOTH CLEAN)I would understand but :I've never asked him for us to have unprotected sex. I'm actually the one who made him understand that it's important to always use condoms. I'm the first person he dates with whom he "actively" uses condoms.He got the std from a girl not a guy (he's bisexual).Before he got the std from the girl he dated at least 3 other guys with whom he used no condoms.Sooo... I don't really think the his reason makes any sense. Correct me if I'm wrong.The fact that he's bisexual doesn't bother me per se. But he has a sexual preference for girls (but feels more emotionally connected with guys). I've asked him if that is the issue. He said it is not. So in the end all this just leaves one person to blame. Me...as much as it hurts.Sometimes I feel like I'm being decieved but then again I ask myself why would he spend so much money, time and energy to put on this façade only to hurt me? I don't think so. Also despite all this his love does seem pure and real to me.I'm confused, scared, angry at both of us and afraid of loosing him and myself along with this.Any advice please