I've asked myself the same thing.Page 2 and most people give the same advice
Eat well, sleep well, exercise and all that... but it doesn't take care of the mental side of the equation.
OP explicitly said that he doesn't enjoy it as much as he used to even when the physical part is under control.
This to me is very much psychological.
I used to enjoy going to clubs and bars, loud environments full of people in my teens and 20's. Now, I'm in my 40's and would rather spend time with friends and family in a quiet setting. I'm at a different stage in my life and it's perfectly fine.
I'd argue the same analogy can apply to sex. If one doesn't feel like having it, why do we force ourselves to behave in a different way? Does having sex very often validate something??
Nothing makes feel more alive and exhilarating than feeling really horny.
Even when I don't feel horny, I want to feel horny.
It also satisfies needs for intimacy.
It's the life force.