I think compersion is a lot more common than we realize, but it's also not always utilized - and that's when we fall into these mental traps that actually hinder us from achieving what we want in life.
As I've said to many others in the past, poly definitely isn't for everyone. I do really appreciate a lot of aspects of monogamy. I'm definitely ones a deep emotional and sexual connection with someone in order to operate in a relationship. For me, I just realized that I'd also like the opportunity (whenever that organically appeared) to have that with others as well.