My x gave me a laundry list of all the things I did "wrong," so I quickly went about making changes. That just pissed him off! saying, "why couldn't you have done this earlier?! You should have KNOWN what I wanted without me having to say anything!! I knew you loved me, but you had a funny way of showing it." Now, I was the w he always wanted (the changes were not a big deal; it was trivial bullsh!t), so I blew his validation for having the undisclosed affair!
They don't do any internal work, so they really don't know why they are drawn to OP, so they guess it must be our fault. If they are unhappy, they look around at the biggest connection in their lives (us) and say, Oh, this must be why I am unhappy!!