Do you have it? In case you don't know what it is - it's the act of being jealous of your SO's PAST relationships.
I have it. Badly. And one of FI's exes just added him on Linked In last night and I thought "Oh, that's nice, she wants to be friends again," because she despised him after they stopped dating. I even encouraged him to add her on Facebook, which he did.
And now I'm inwardly freaking out. What is wrong with me? And do you experience backward jealousy too?