yeah, don't complicate it too much. I can understand his point of view though, even though I'm a woman...

Even though sex with my boyfriend is very satisfying, sometimes I'd prefer just to have oral sex (or 69 with him), or just spend some time w/ myself and a dirty story website :P Other times, I'd rather just give and not receive myself.

If really varies due to stress, energy level, and just horniness at the time. He's probably like that.

I'd say don't stress too much over it, unless he starts ignoring you in other ways too.