Hi honeybee,
that happens to me alot of the time, I think its mainly due to stress or tiredness and maybe sex is boring, cyclical and repetitive. Try something different. I always like to be courted by a guy. He could simply tie a red ribbon around the remote control and let me watch my favourite SEx and the City, give me compliments, take me a to a suprise dinner.............but you know the best suprise, and I think this might be the ticker for you and your girl, give her a nude massage from top to toe with lots of baby oil, it's heaps of fun. Make is sexual and sensual with lots of teasing and revese body slides, she'll love you for it. xxx
PS: lots of traditional stuff to, like the candles and music, make her feel like Cinderalla darling.