C.W.
Sounds like my ex-husband! Seriously, he had the sex drive of plant life. We did counseling, adjusted meds, tried fantasy scenarios, etc. And now we are divorced. While I have always been quite sexual I had no idea how important balance in that area of my life was and as you say, the older I got the more cranked my drive has become.
Do counseling, bargaining, whatever you need, to achieve balance between your two differing levels of need, the longer you let it go the harder it is to fix. My boyfriend was put on notice when things got serious between us that I will tolerate no shilly-shallying in the sack. Once a week you are tired, fine but don't make a habit out of it.