I respectfully suggest that you address why you are not having sex. Is she good with this? If so, you are looking at a real possibility that she is asexual. This is not to say that she cannot 'have' sex; but it means that even if arousal and climax IS possible for her, it's likely that she doesn't experience sexual desire. This may illustrate the difference.
If a man and woman have sex a half-dozen times in one day, HE is likely finished FOR the day. She on the other hand may want to continue. It's that female sexual stamina thing. Say HE can't respond again. If she asks him, 'don't you desire me,' the answer will be on the order of 'hell yes -- I desire you!' It's just that after a half-dozen ejaculations, he is not capable of experiencing AROUSAL at this time. Tomorrow is another matter. So he has DESIRE, but cannot experience further AROUSAL at the present. So he can't perform. So an asexual may experience arousal, but won't likely or often experience ongoing DESIRE. The difference matters.
So ... what is the reason for this absence of sexual activity?