Financial infidelity refers to the act of withholding important financial information, such as debts, expenses, income, or assets, from one's partner in an attempt to deceive or control the couple's financial situation. This can include secret bank accounts, hidden investments or holdings of cryptocurrencies. This phenomenon can have serious consequences particularly during divorce.
I don't really support this, couples hiding things from each other suggest a union lacking trust. I grew up to my mother knowing my father's investment and financial dealings and I'll not want to get involved with someone I'll be hiding my funds for. It really sucks and would be very de-energizing.
Yes, if found out that one partner is hiding some financial details from the other, it may cause some resentment on the party if the faithful one. In a marriage, you should marry your friend and someone you can relate things to, even your secrets, so what's the point hiding it? Unless of course you notice your spouse isn't as honorable as you thought.
If I have your seed phrases by mistake for hidden funds, since you had the mind to hide it. I'll be friendly enough to take half of the funds and leave half for you and I'll not agree I did it, after all, you didn't want me having any in the first place.