Seems to me like this is more about personal satisfaction. Sex is a great way to release endorphins and additional hormones that contribute to ones happiness/ overall demeanor. If someone has a regular release of “happy emotions” then they tend to be happier on the job, which can lead to better job performance, which in turn, leads to more raises/ more money. I also believe the type of sex you are having is important. For example, if a man has an unhappy sex life, even if it is on a regular basis, that would lead to more stress. It’s like eating a bad meal or not enough food. Yes you are eating, but are never quite satisfied. But to someone eating 5 star meals on a regular basis, they are always full and satisfied. With that being said, if your lover is providing stimulating, and satisfying sexual encounters, then you are more likely to be a happier person, thus igniting a positive cycle.