O.C.D.D (Obsessive Compulsive Douchebag Disorder)
You're stuck on a lover who's a complete waste of space. They're a lying, sneaky, stupid mess, but you still believe they're perfect and will take them back even when they're already married to someone else.
'He said he never loved her. I believed him.'
'He's got a kid now, but I still want him back.'
'He's cheating on me, but he said he's not.'