Feeling grumpy

I had good friend but she stuffed up did some things to me that really hurt and I got mad. She then proceeded to make the situation all about herself and now I absolutely can't drop this thing that I have going on and my boyfriends sick of it and doesn't want to talk about it. I don't know what to do. How do you stop being angry? My boyfriend is friends with this person too and wants to still be friends with her but not only do I have a serious hate on for her but I'm a jealous person and him talking to someone I don't like makes me mad. I know it's irrational and I have no reason to be angry because he assures me that I'm the most important person in his life. Why is he still talking to her when he knows it makes me mad. I just really needed to vent. So mad. Such anger.