I wonder what you really mean by this. Do you wish to have had sex with a greater number of women? Or do you wish you just had more sex with your partner/s?

If it's the former, I believe this is something all men want deep down. Religion has done well to squash this desire and many deny they have it at all, but they do. But it's like chasing the dragon. I don't think you can ever really satisfy this urge.

If it's the latter, why did you not have more sex at the time? Did you want it at the time? Now I live with one partner I have almost as much sex as I want with a single partner. But it's a lot less than I used to have/want.