My partner and I have been together for a year. We used to have sex five times a week, but now it is down to once a week. She started taking birth control pills three months ago. When someone has a sudden change in his or her sex drive, it's best to first evaluate whether there is a biological process interfering with sexual arousal.
Medications can affect libido.
Birth control pills, for example, can cause the libido to go down or up. It's difficult to predict what effect specific medications will have on an individual. For many women, sexual arousal is closely linked to the state of the relationship. Like men, they do have a higher level of arousal with a new partner. But when interest in sex lessens, it's often because a man is not giving them what they need emotionally or what they need during sex.