I like @marinelife‘s advice a lot. Counseling would help. However, I doubt he will be willing to go. He just doesn’t see that there is anything wrong.
I’ve been in the frustrating position where I wanted sex and my wife didn’t. It cause very serious problems in our relationship and to be honest, even though we are doing much better thanks to counseling, something has been lost. An important something.
I think you are feeling the loss of that important something, and I’ll be it’s a bit scary, especially since you just moved in. I think it would help if you found a way to tell your bf how serious this is to you—i.e., that you are thinking of moving out.
Now, one reason people don’t feel up for sex is they don’t feel connected to their partner. If he feels that, he seems to be denying it. There also could be performance issues. How often did you have sex before you moved in together? There are surely psychological issues. Maybe he was interested in you when he had to romance you, but now that you have moved in, he may feel he doesn’t have to do that any more. Maybe he doesn’t get aroused unless he has to chase.
It is too early to say you should move on, but you do need to develop some open and frank discussion with your partner. The fact that he does not hear your concerns should be disturbing. He should be concerned about your feelings and he seems to be not taking them seriously. Not good.
If your relationship is ice cold, then it has to be heated up. This will take work. Like I say. You have to both be willing to talk and listen. A therapist can help. But you can do it alone, with the help of a book such as the one @marinelife suggested. If he won’t participate, that is very telling.
Good luck!