First off, What the hell. Why are you going to depend on your future spouse for your future stability? that's just belligerent and irresponsible on your part, and a little selfish too coz now you'd have to put the trouble of tending to yourself in the future to your husband/wife. That's just stupid.
But let me humor your question for a bit. Suppose you'd be given the chance to marry between someone who's fiat rich and someone who's cryptocurrency rich. I'd be practical and pick Fiat Rich. With its long-running stability, and the fact that Inflation works for the Rich, it just means that I'd get safety nets after safety nets, ensuring that I have a future to rely on. Which couldn't be said when it comes to cryptocurrency. The price of crypto is unstable, you could become cryptocurrency rich today and live in a cardboard box in abject poverty tomorrow, which doesn't happen in fiat rich people.
I'd choose crypto wealth, that's on my own side, I'd be the the rich spouse not the other way round, marrying my wife because she got money. I'm taking on cryptocurrency because of divorce purposes, she may not know I've got some amount of crypto in my possession. So, only the physical properties can be shared.
I disagree with your reason of picking fiat over cryptocurrency. It depends on the crypto and as well the fiat. Some fiat currency can lose it values drastically too similar to some cryptocurrency. But, as for Bitcoin I don't think your views tally with my way of thinking. Even if it drops too bad, it'll definitely rise again. Believing that a person who holds Bitcoin today will go broke or poor tomorrow, however severely, is simply a lie. They have the opportunity to sell their assets if things dont sit right with them again. You sounded as if the price of Bitcoin can go to zero without any warning.
Considering that the growth of Bitcoin price depends on the number of people that holds it, like a positive feedback loop and negative feedback loop, everybody has to sell their coins to make a crypto rich man poor. And it's almost impossible, because the person during the cause of the bearish race can also decide to swap to fiat.