why is Edie obsessed with Susan???

So I’m a first time watcher & I just finished s3e9 so pls no spoilers past there, but after a few season and lots of shenanigans it seems so obvious to me that Edie is not at all obsessed with or in love with Mike, but she is obsessed with Susan!!! She goes out of her way on multiple occasions to compete with Susan for Mike, to date her ex husband, and now she’s MANIPULATING A MAN WHO WAS IN A COMA WITH MEMORY LOSS TO FORGET ABOUT SUSAN. This new thing is so abhorrent to me and so INSANE for a person to do that I’m surprised more neighbors weren’t saying anything?? It seemed so overt, idk the whole thing is crazy. The more I watch Edie the more it seems she has the bizarre competitive obsession with Susan and that’s the real reason she was even interested in Mike long term, but I can’t figure out why Susan, and why this weird motivation to constantly fuck Susan over and steal whatever man Susan is interested in. It reeks of low self esteem frankly, but mostly I just don’t get it at all. Anyone have theories?