The level of sex drive varies from guy to guy. On one end of the spectrum are guys who never seem to be satisfied. On the other end are guys like yours who have little to no sex drive. It is estimated that as many as 20% of males are on the lower end. You’re not alone in this. And it most probably has nothing to do with you! The reason he was able to perform in the early stages of your relationship is that the romance was new and nature was responding. That’s not unusual either.
What is unusual in this case is your boyfriend’s acceptance of the situation. Before he resigns himself to little sex in his life, he might want to talk with his doctor. Medical causes of low libido include: low testosterone levels, high prolactin levels, pre-diabetes, hypertension, or chronic fatigue – to name only a few. If he is medically healthy, there might be a psychological problem like depression, inadequate skills for managing stress, or reaction to a past traumatic experience.
Needless to say, you can’t argue someone out of a medical or psychological problem. Instead, express your love and concern and see if he is responsive to finding out just why he isn’t able to enjoy this part of life with you. Explain that there may be good reasons why he is unresponsive sexually and that it’s important to you to make sure he is medically and emotionally healthy. Once you have that information, the two of you will be better able to decide what to do. It may be treatable. It may not be.
if there is a condition that makes it unlikely he’ll want sex more often, can he take pleasure in pleasuring you? Can you accept that it’s really okay for sex to be one sided most of the time. If your relationship is perfect outside of this one area, do think it through carefully.
I wish you well.