Your boyfriend does not seem to feel any regret about cheating on you and he is keeping his options open by staying connected with this other woman. This is not OK. If you allow the men in your life to disregard your feelings and play on your self-worth, you will continue to attract these similar dating patterns.
There is always a happy medium that can be implemented to keep your partner and your best friend on civil terms with each other. Be realistic about why things are a problem between them and hear what they are telling you.
You have the right to know where you stand after being in a committed partnership for over 1 year together. In fact, you should know by now!
What good is going to come out of treating your partner, friends or family members with angry words and bad behavior? Isn’t this really about YOU and being unhappy with something that is (or isn’t) going on in your life?