You absolutely *do* have power! Are you breathing? If so you have power.
Do not validate bad behavior. It will simply give him an open arena to exhibit MORE bad behavior. I do think validating feelings (to a degree) is important but anything more is not your problem any longer.
If your H is looking for validation that him leaving a marriage is okay then he should look elsewhere. If he has conjured up in his own mind you will still be his buddy after this he is mistaken. Your power is right there. Detach yourself from this man and go about your life. Do not be his pal or his emotional sounding board. Be pleasant and civil and proceed forward.
Fixing things may or may not be a viable option but NOT exposing yourself to further hurt from a man that likes to take but fails to give is done.