Had a friend who kept going back to her gross, cheating, controlling baby daddy. He ruined our friendship eventually...I barely ever saw or heard from her when they were together, and I was so pissed that she put that asshole before our friendship.
When she tried to reach out I chose to ignore it...I was so angry at her. 10 years later I've matured a lot and realize she was probably just going through a lot and didn't know how to deal with it all. Wish I'd been more understanding and kinder to her when she needed it.