Grudges

I'm the type of person that doesn't hold grudges, but it seems like I have been holding one for almost a year. Some things are hard to forget. I was always taught to forgive not forget. If you forget then you'll keep letting the same thing happen. Right? For me it's hard to be friends with, conversate, speak to, or even be in the same room with anyone who betrays my trust in any way, shape, form, or fashion. Especially someone who was supposedly my "FRIEND" for a number of years. Am I wrong?