Jealousy is conflating love with ownership
This doesn't ring true for me. If someone rejects me, I get sad but not jealous. If she subsequently gets with someone else, I get jealous. I often get somewhat jealous if someone I wasn't particularly interested in gets with someone. But if someone doesn't have a chance to reject me, I experience little or no jealousy relating to her (e.g. if she was in a relationship before I knew her).
This seems a lot more complicated than "conflating love with ownership".
If someone rejects me, I get sad but not jealous. If she subsequently gets with someone else, I get jealous. I often get somewhat jealous if someone I wasn't particularly interested in gets with someone. But if someone doesn't have a chance to reject me, I experience little or no jealousy relating to her (e.g. if she was in a relationship before I knew her).
Sounds like a clear case of endowment effect. People have done experiments that show this bias occurring with ordinary objects like mugs. So yes, it is "complicated", but in a broadly applicable way.
Sometimes our minds suddenly "click" and we see a topic in a new light. Or sometimes we think we understand an idea, think it's stupid and ignore attempts to explain it ("yeah, I already know that"), until we suddenly realize that our understanding was wrong.
This kind of insight is supposedly hard to transmit, but it might be worth a try!
So, what kind of important and valuable insights do you wish you had earlier? Could you try to explain briefly what led to the insight, in a way that might help others get it?