Spousal privilege

Does spousal privilege apply outside criminal or civil cases? For example, if a husband were to be told something in confidence by his wife that would get his wife fired, is he legally free to disclose it to her employer?

My understanding is that spousal privilege has to do with whether one can be compelled to reveal something, not with whether one is allowed to reveal it. Furthermore, it is a legal concept applicable to a court of law, not to other aspects of life such as one’s employment.

It’s actually two separate privileges:

Here’s the Montana statute. The site says other states’ statutes are similar:

So there’s no indication that it would apply in the OP’s hypothetical about one spouse telling the other spouse’s employer about something that could cause the other spouse to be fired.

So, to be more specific:

Also, a final aspect:

I wonder if it has ever been successfully applied to a same-sex relationship that can’t, legally, be considered marriage in the eyes of the state.