Christian Advice Needed – How Do I Get Over The Pain And Hurt Caused By Someone Close To Me Who Won’t Change?

This person, who is very close to me, is utterly selfish and although I’ve explained how their behaviour is hurting me, they refuse to change. I don’t hate this person and I have prayed to the Lord to help me to forgive and forget, but I can’t. I don’t want to have anything more to do with this person and I wish I could just pretend they did not exist. Any Christian insights or advice would be appreciated.