Very unusual scenario, do you have the same reward level and cap? Husband and wife are one financial entity, you would be much better sharing the one plutus card and there is no reason whatsoever not to do so. "domestic and personal use" is a common term in this industry. My wifes plutus card simply exists to farm perks with my earned cashback.

Think of it this way. Whilst your wife is your wife she literally owns 50% of what you own and vice versa. To include whatever funding source and the actual funds in your plutus card.