She is my best friend and I can't imagine what my life would be without her.
That is the point. If you guys are best friends, you DON'T have to be without each other's friendship even as other things shift/change in other areas of your lives.
You guys could choose how you want to behave as you navigate this (the present) and you guys could choose how you to want to behave toward each other later (the future) -- out of respect for what you shared before (the past).
Remember to BREATHE, and be calm as you both discern for yourselves what is next in store for you.
Hang in there!