I have had a similar situation with the wife of a guy I have known for about 25 years. I only see them once a year but every.single.time she complains that I have unfriended her on facebook. Loudly. While in my mind, I can say 'No, Dina, I made a mistake accepting your facebook friend request. I've NEVER liked you!', I know that if I said it out loud, it would probably see me cast into the ninth circle of e-hell. Instead, I smile and say 'Gee, facebook sure does some strange things sometimes doesn't it?'. Yes, I'm lying through my teeth, but, d'you know, some argument just aren't worth having. Have a clean-out of your facebook friends would be my advice.