Kuro no Senki: It seems that I, who has moved to another world, is the strongest only on the bed - Chapter 7.1

I can understand his desire to make her his woman but his desire to overwrite her past is just immature jealous that is common with those unfamiliar with dating experienced women. You can’t have or change her past, you can only love her in the present and have her future. You just need to get over your insecurity and move forward.

Also I guess the myth that young men can go for more times comes from the fact that most people don’t keep in shape as they age. Same for women. Either you are in shape or you aren’t, simple as that.