Suddenly not liking sex?

Lately I haven't been wanting to have sex with my husband, it's not that the need isn't there or that I'm not attracted to him. I'm not sure why I'm feeling this way, I absolutely love the foreplay but when it comes to actual penetration I lose all interest. I'm going to see a therapist soon to see if they can help but I just want to know if anyone here has ever had this problem?