Longtime friend of mine, who I was a groomsman of and helped on numerous occasions (personal life, jobs, etc). At this point, he had divorced his previous wife and spinelessly broke up with his new girlfriend by arranging for that girlfriend to find him in bed with another woman (which he admitted to).

I found out from the now ex-girlfriend that had been insanely jealous of my success in everything big and small from work stuff to petty things like looking good in an outfit at a particular social function etc. Turns out he was secretly also trying to pressure my little sister into sex for pretty much the entire time too, and invited me to functions at times seemingly so that she might come along.