There is a whirl wind of things that can affect libido negatively like fatique, a boring Spouse(shake them up), Depression, as already mentioned on here. I think strong genes are helpful and definitely a Good testosterone level is necessary. I’ve had Diabetes for 47+ years and…I’d rather give up the occasional cherry cheesecake.
Doing Kegel exercises(developed by Dr. Arnold Kegel) strengthen(sp) the Female and Male pc muscles.