as Sabrina said - Welcome!
I'm very glad you feel comfortable enough to ask questions. Is definitely the way to get to know people on the board and there are so many cool people here it would be a pity not to get to know atleast some of them!
to the TFP members
The other advice given is pretty good - trying to get her to atleast acknowledge there may be a problem and looking at the past frequency of sexual intimacy that is.
To try to make the sex better, when you do have it, you could try intensifying lotions (usually designed for women but work when applied to the head of the penis) or tell her you're using one and then use a numbing lotion (I don't RECCOMEND that but it might help - lying to your partner is never a good idea).
If she's at all kinky you could also try clitoral clamps - they can help to hold off an orgasm, ONLY if she's a very clitorally (is that a word?) stimulated girl though. If she's a G-spot girl that won't help at all.
I kinda of agree with you on the romance front - you shouldn't always have to go the full candles, massage treatment. It's nice on special occasions but not everyday.
Do the two of you have children - if so how old? Any possibility that may be having an effect on her sexually? Or could is be early onset menopause? (I know she's young for it but it DOES happen) that would muck up her hormonal cycle and could be throwing her libido out of whack.