HELP:

My boyfriend and I have been together for 8 years, and sex just gets better and better the longer we are together. He is so attracted to me and makes me feel beautiful EVERY chance he gets! However, for the past year or so, when we have sex and he climaxes before me it’s EXTREMELY difficult to get him back hard for enough time for me to catch mine IF even at all! He takes it so hard and gets so upset with himself, but I tell him it’s okay and we can always try again the next day. What could that mean? Is it something I’m doing wrong? Could it be his diet? Or something more serious?