The Six Stages of a Mid Life Crisis, by HB. :)

[Spacey]

There's no clear consensus on what causes or triggers a MLC, nor on what those who go through MLC have in common (there's not even a consensus on whether MLCs are a thing or not), but, at least from my limited reading, the hypothesis with the most support is that the person going through MLC is running away from some unresolved issue.

If you're not at the heart of the issue -- i.e. you didn't cause the issue, or the issue doesn't have to do with some aspect of who you are, how you behave, or how you treat others (your spouse, in particular) -- then then you can't solve the issue. This means any attempt you may make to solve the issue is either A) going to actively prevent your spouse from from dealing with the issue, so that it lingers, or B) going to enable your spouse to avoid dealing with the issue. So that it lingers.

If they're running away from the issue, forcing them to confront it on your terms will do little more than make your spouse highly resentful toward you, and break whatever amount of trust they currently have in you. Coddling your spouse and supporting them and their decisions while they're running away from the issue both leaves you playing the part of the doormat, and validates/reinforces their desire to flee. It also, potentially, sends the message that you don't think they can deal with the issue they're trying to avoid, and make them, eventually, feel like a charity case.

So, yeah... You don't want to try and help. Not if you haven't been asked to help, that's for sure, and even then, only if you've been asked to help in some very specific, spelled out way. Anything else is just likely to hurt the situation.