Do you have any idea what you're talking about? Prolactin rises once a male reaches an orgasm to cause a refractory period. Some people get more prolactin released than others leading to some people needing a longer refractory period. It has no impact on the gains or lack thereof.
Humans rely on sexual reproduction to procreate meaning sex is a biological necessity towards extending your genetic material. If sex caused any long term issues don't you think we'd either have adapted to it by now or died off as a species??? Regardless, even if it did cause a problem which it doesn't, who here would realistically stop having it for this reason?