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?