What would you do in this weird situation?

I have/had 2 friends who i was friends with (seperately) for years. we all used to hang out, and they later became friends with each other and I started hang ing out less as our lives went in very different directions. i work with one of them now and she lives with the other and they hang out a lot. i feel weird about the whole situation and just want to distance myself from it. its odd when you hear about someone you used to be good friends with from someone else now. i dont think there is a chance to rekindle our friendship. is the best thing to do just seperate myself from the situation?