Why on earth would you let someone who is not you anywhere near your private key? No security system in the world can fix user fail.

The difference is when your ex releases your key and you are using this system then everybody can read your email instead of just the NSA and the recipient.

So, what you are saying is that nobody else, but you, should ever have access to your private key, right? I'm pretty sure that's PKI 101, which I think was Karunamon's point; and, I'm pretty sure the solution to your proposed 'weakness' in this system is not technical.

He edited his post and my reply doesn't make sense in context now

Since people share passwords with (at the time) trusted people quite frequently, it seems like a scenario one should plan for.