When people talk about security and privacy all I think of is not hiding my private keys, seed phrase from family but rather my online presence or internet activities.

I don't know the type of relationship those who say they do not trust their spouse or children have but it's certainly weird to be in a relationship where you don't have trust then why are you there in the first place if you can share such secret with them? anyways we are not talking about relationships but at least it's paramount to have one or two person which should have a clue of what you have and that person could be anyone (family) as long as there is presence of trust

That bitcoins of yours is considered conjugal property when you acquired within the marriage, meaning your spouse has a right to it. If you truly love your spouse, sharing the private key might be a wise move, you never know what could happen in the future. In case of death, at least your long-held asset can still benefit your family, especially if you’re the breadwinner.

You can still maintain the privacy you want because in marriage, the two of you become one. Sharing the private key doesn’t mean losing privacy, it simply means that only the two of you have access to the Bitcoin.

Bitcoin wallet secured only with private keys, and anyone who has that has unlimited access, if you have private keys meaning you can do anything with the fund inside the wallet. That's why sharing private key to anyone is risky. However there is option like multisig wallets, which require several confirmations to do transaction. There is also more conservative way like arrange inheritance letter to give your wallet to your trusted person, rather than giving them total control of your fund while you are still alive. 

In my opinion, privacy does not mean hiding your important information from your family, your wife and children. We basically work to secure the needs of the wife and children, so I do not consider them something different and I do not hide my privacy from them.

But in some cases when the spouses do not agree or are thinking of separating, then it is wise to maintain your privacy in front of your wife and not reveal your sensitive information.

Also, if the children are minors, privacy should be maintained and sensitive data should not be given to them so that they do not misuse it.

Interesting question, but I think we have to understand that everyone has their own definition of privacy, but there is definitely one universal definition of privacy, which is how someone control and access their own information at their free will. Now, the reason why I actually feel that everyone has different definition to privacy is because people tend to share sensitive information to trusted parties like the bank related details that you mentioned, but do you know why's that?, It's very simple, the organization behind these banks is what we call central authority (centralization), so it would be easy to meet them up for assistance whenever anything goes wrong.

For example, in a case where just you and your partner have the passcode to a bank account, and all of a sudden, you got debited of a massive amount, if your partner eventually denies not spending the money, you can definitely go to the bank to make proper confirmation and ask about the transaction. But with Bitcoin, it's quite the opposite. Your Bitcoin related matters (phrase and private key) should be kept as safe as possible because there is no central authority to consult. Don't even think about the police, because the last time I checked, they don't work for a Bitcoin. Bitcoin does not have an head office. You should know by now that people's Bitcoin gets stolen even under their nose. So, it's not just a good idea. You might feel that a forensic research might help right?, But is it not better to be on a safer side by keeping your details to yourself, rather than becoming a victim at the end of the day.

Not everyone betrays each other for money, just because one man was betrayed by another and told you, doesn't mean the rest will be just as bad. Furthermore, if you can't trust anyone, not even your wife or mother, then don't expect anyone to trust you, and basically, you're not someone worth trusting either . A person who never trusts anyone does not deserve any trust in return.

Honestly, money is very important and the most important thing in society because without money, my family and I would not be able to survive in this world. But between family, husband and wife, children...I will choose them because if I lose them I will never find them again. For bitcoin, money...they are all physical and they always exist in this world and it is not too difficult to get them back if I lose them .

There are some things I see as stupid. It may not be stupid to you and some other people. If nothing happens to me, my spouse and children can not be able to access my coins. But I would have taught them and let them know how they can access bitcoin wallets and exchanges. And I may even be sending them some money in coins for them to exchange it to fiat themselves. If your spouse want to do something stupid about your property that you bought with your name, you can easily recover those back but when it comes to bitcoin which nobody knows the owner, the recovery will be difficult or impossible.

Privacy does not mean that you keep secrets from your family because your wife is the first person you should trust and share yout secrets with. The same goes to your kids because family members are not strangers but part of you. Trust and love should be built in the family so that we can trust each other with out lives. Your bitcoin is safe with whoever you trust in your family.

Your offer to trust access to bitcoin wallet works only if these people can really be trusted. Otherwise, you are only creating a very strong threat to the contents of your "wallet", be it a bank account or a crypto wallet.

As one literary detective character said, spouses are the 1st suspects in a crime. Look at the divorce statistics. Are you really ready to trust your money to those who are ready to bite your throat after a couple of years of living together?

Everything is good when it is done well. If your spouse can be trusted (deservedly entrust) with your crypto wallet, then this is wonderful and even correct, from the point of view of risk diversification (if an accident happens to you).