What has been your experience with compersion?

In a writing titled: (some may find this [NSFW] because of images used in the article) Compersion: The Only Way Out is In the author states that “compersion is the full appreciation of another person’s pleasure and indeed their existence—something many relationships could use a lot more of. If we could indeed get there, this would be an excellent resolution for jealousy and much besides.”

The author notes that the idea was developed in a community where people explored polyamory. Yet, I imagine, that even people who practice monogamy have experience with the phenomena.

The word hasn’t made it into dictionaries and it is something that I don’t quite understand. I am thinking hearing others write about their experiences or thoughts will help clarify it for me.