If you buy a bitcoin, store it in private manner, no other people can know where you store it.

Per law, any asset is bought during your marriage time will be considered as co-owned by you and your wife (or husband). It should be split in divorce case.

Morally that husband made a bad thing as he wanted to hide and steal that money from his wife. I don't support it and I feel happy that the wife detected it by herself. If that man stored his bitcoin not too good, safely and secretly enough, his coins can be detected by his wife as we knew but can be found by other people in his family too.