I have read that there is scientific-evolutionary-biological evidence that homo sapiens were not meant to be completely monogamous. For example, they’ve found that only a small percentage of sperm actually are able to impregnate an egg; the function of more than half of sperm is actually to destroy any other males’ seed that may…
I once read a book on sex that suggested that healthy sex has at least three aspects: respect, honesty, and consent. Within that framework, the book suggested, do whatever your dirty li’l minds come up with. That definition made a positive impression on me. And now, years later, having developed in my Buddhist practice, I like those three as good guidelines for a basic foundation of “right sexuality” that fits with the modern world that I live in.