Short answer: You can't. Long answer: You cannot force, cajole or beg a woman to want sex more. It must be up to her. What you CAN do is talk with her openly and honestly and try to find out why she doesn't want it as often as you do. There can be a lot of reasons that a woman is not interested any more, ranging from physical to emotional. Physically, when a woman gets older, her body goes through a lot of hormonal changes that can cause anything from painful sex due to lack of natural lubrication or no drive due to hormones, depression or other issues. Your being faithful has absolutely nothing to do with her drive. Based on your martyr-like comments at the end, I'd venture a guess that there are other issues here than her lack of interest, and add that you cannot guilt her into more drive. You must open the door to communication, and find out whether or not she WANTS to have more drive. If she does, there are natural supplements available at health food stores such as Damiana, Steel-Libido and ViraMax that DO work. The only catch is that she has to WANT to have more drive. If it isn't physical, seek counseling.