I know of many monogamous gay couples, Joao Nascimento, and plenty more who value monogamy but torment themselves over not being very good at it.
I have a young friend in his late 20s who drives himself crazy worrying that his boyfriend is cheating on him.
I know another couple where one partner is cheating, knows he isn’t good at monogamy, feels awful about it, but seems unable to embrace the idea that sexual fidelity doesn’t have to define a healthy relationship.
He wants to be monogamous, even though he isn’t.
Then there’s Leo and Hal, a couple I knew who were together for 40 years.
As far as I know, they were entirely sexually exclusive with one another. And they seemed quite happy about that.
You just never know!