Wow. This thread in itself could be a basis of a study in sociology, especially marriage.
I'll be frank. I understand everything posted here intellectually at least... But personally and emotionally? I don't get it. When I read some of these posts, I get the feeling of house mates, or business partnerships. When someone says "What happens when you have retirement funds, health cover, high network worth, and she's still in debt", my first thought is how??!! Is the husband going to go on first class exotic cruises by himself, while she's struggling meet her share of the power bill?
When I look at this situation, I suspect there's some pretty deep unaddressed issues here. Did OP and partner agree to take on a FIRE lifestyle? If so, was the commitment from OP's spouse genuine? If it was genuine, why is she unable to keep to her commitments? Is it a mal-adapted coping mechanism? I had a friend who when he got stressed, would just buy random stuff on eBay. Dad had to bail him out to the tune of 100k, but his wife left him anyway. If OP didn't obtain his spouse's agreement, or got lip service to it, there's a bigger problem right there. Did he coerce her into it? Did she deceive either because she wanted him to give it a rest, or had no intention ever of working towards the same goal.
I suggest that working at this problem at face value, will either end in divorce, or the same issue happening again. If OP and his spouse don't get to working out what is going on underneath this issue, I don't hold out much hope for them.
My view is getting personal, rather than practical now. But the more I see of "contemporary" marriage, the more convinced I am that traditional marriage got it right. If you are married, and you still think in terms of "my money" and "your money", you're setting yourself up to fail. Because a team doesn't have my goals which are funded through my money, and your goals which are funded through your money. It doesn't work like that in business, and it definitely doesn't work like that in marriage. There's no my money or her money, or my income or her income, or my desires, or her desires in our marriage. I meant it when I said 11 years ago:
Rebekah, I give you this ring
as a sign of our marriage.
With my body I honour you,
all that I am I give to you,
and all that I have I share with you,
within the love of God,
Father, Son and Holy Spirit.
Even though I want to lean out our lifestyle, I would never push it to the point where my wife felt she had to deceive me to get something she wanted. If that happened, something much, much more serious than financial infidelity has gone wrong.