Honestly, still have your friendship with your friend as they are more important to your life then the person you like or liked as it is only a crush. Crushes don’t last long. I guess you would still have that awkward feeling of having your friend date someone that you liked but in life you go through many different crushes and loves. You will get over them. It may affect you for a while but you will be completely fine. The situation that you are in would be worse if you dated their ex and lead to further complications. Just remember you should be happy in your life and shouldn’t have you world revolve around a single person especially if your in school / collage as you are young. Have a wonderful day!