Prenups don't work in Finland. But, they also only cover what people have come in with for the most part. The investment between might be a different matter.
People do it for birthdays; "It's my birthday and I want to treat others".
In Finland, this is done in the workplace. people take a cake or a bag of candy or whatever to share on their own birthday, rather than expecting colleagues to remember.
Basically being there, and putting in the work, to make the relationship work is necessary.
Presence. People spend their attention on a screen, not on their relationships these days I think.