The amount of time I spend in close proximity to females is inversely proportional to my desire to grind. When I'm alone on a weekend, I have a powerful urge to exercise, read, make money, socialize, and produce. With a female in close quarters, I want to eat food, lay around in bed all day, sleep, and consume pointless media.
My guess that this relates to our evolution as a species. Why does your ventral tegmentum shoot dopamine into your midbrain? Because you did something to make yourself a more desirable mate. These reward mechanisms have evolved to reinforce behaviors that promote reproductive fitness. Everything we do is directly or indirectly linked to the need to procreate. Our mood rewards us when we do things that advance this goal and pushes us to seek this fulfillment.
Once these mechanisms are being satisfied, though, there is less motivation to seek higher levels of reward. I suspect this contributes to married people gaining weight and taking fewer risks in their lives, since the basest impulse for the sex at is (at least in theory) being satisfied. This is coupled with the societal expectation to settle down and devote your life to our family instead of your own interests, which goes against a man's hard-wired urge to maximize his reproductive fitness through risking failure for accomplishment.
I like the occasional "girlfriend weekend" because it's nice to take a break form the game, but it ultimately goes against my nature. When Monday morning comes, I always choose personal fulfillment and productivity over comfort.
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