Paul Simon nailed the answer to this question. No need to blame anyone for not being who you wanted/needed them to be. Just go. No one owes you a damned thing. You are not entitled to their participation in your fantasy of how it's supposed to go. So yeah, just drop off the key, get on the bus and do what needs doing .. but with as little damage as possible.
https://youtu.be/K4xoHjNjxus
https://youtu.be/K4xoHjNjxus