Monogamy is like math
Monogamy is like math. It comes naturally, as long as you practice.
Well I've written before about the important distinction between liking versus wanting. "Desire" as it seems to be understood popularly is nearly 100% WANTING. There is a thing out there that you don't currently have, and it's appealing and attractive, it draws your attention, it excites you... you desire it. That's wanting. It's smelling Local Burger as you walk down Main Street and spending the whole day fantasizing about it, and then you get there and bite into it and it's AWESOME.
Boy skippy can it be enjoyable.
(What happens next, inevitably, is habituation tied to satiety, and it gets less awesome with every bite.)
But there are other things to enjoy, beyond the experience of wanting.
Imagine you're a gloriously long-term couple, and it's Friday night. The two of you have this thing you do every Friday night, where you cook a glorious dinner together - you drink the wine that was meant for the sauce, you end up feeding each other half the strawberries that were intended for dessert (if you're honest with yourself, those berries were never destined to make it that far), you sit down to a meal you made together, for the thousandth Friday night in a row, and you look into your partner's eyes, and what you see there makes your heart flip over.
That's liking. Enjoying. No "desire." Just pleasure.
(What happens next is that every bite is as glorious as the last, you go slowly... and yeah, you eat less.)
Which is better? Neither. It's not about better. They're DIFFERENT.
Our culture seems to emphasize and pedestalize desire, and I think maybe people who lean more in the direction of pleasure than desire have to make some choices, untangle some cultural knots, make some individual choices about how they want to experience and express sexuality. But they're different ways to enjoy.
This is my long way of saying:
Monogamy is not the problem.