I haven't lost much of my sex drive over the years (I'm 54) but I didn't start out with a lot. My wife has always had a much greater sex drive than me and she's 8 years younger than me, too. My libido has always been on the low side of normal for a guy and hers is greater than any woman I've ever known. That was a source of friction between us in the beginning because she, quite reasonably, expected me to be the "man" in the relationship. So, after the honeymoon was over and I started having "headaches" she took it personally.
We finally realized that neither of us were well suited to the roles that our culture assigned us. So we switched. She takes the lead in directing our sex life and I do whatever I can to please her whether I feel like it or not. She makes it interesting though. She's very aggressive sexually and I'm passive. She likes being in control, I don't. The funny part is that taking the submissive, passive role is a huge turn on for me and my sex drive is greater because of it.