Could it be that he isn't in the mood because he feels that you are pressuring him into it? . . . it needs to be a spontaneous thing . . .

The other thing to remember is that he may feel unable to perform while on his current medication . . .

I definitely think you should ask him for clarification on where your relationship is at. Sit down with him with no distractions and ask him, and don't leave until you get a straight answer.

That's my advice, anyway.