I feel like I am losing my bestfriend.
Wow, why do you feel you are losing them?
My best friend is cheating with my girlfriend.
It must hurt that they are cheating behind your back. It is acceptable to be angry with your best friend and exit your friendship.
My friend always cheats with everyone and I know it is just how he is, so it is probably a good time to find a new best friend.
Hey, It is good to recognize the truth even when it hurts. Do you plan on confronting your girlfriend too? This seems like such a bad position to be in for you.