Nudge theory doesn't really work the way it was originally advertised.
e.g: They used "nudge" theory to encourage people to eat more vegetables - put the vegetables/fruit in a prominent place in the canteen that children have to walk past/see and more children put vegetables on their plates. Success! Except that more vegetables got thrown away - children were choosing to put vegetables on their plates but they weren't actually eating it.
They tried to use nudge theory right at the start of the Covid pandemic. Rather than lockdown (and have to pay restaurants/businesses etc) the government was just going to try to persuade people in both obvious and very subtle ways that going out etc was a bad idea. People became very judgemental of other people's choices "I went to Luigi's last evening and it was absolutely rammed. Its as if no-one around here cares about Covid..." but didn't change their own behaviour much at all. See also the amount of people who have absorbed the message that large cars are bad for the environment but have a new 4-wheel drive because.....
If people (men) secretly want to settle down and have families, then it might give them more of an excuse/reason to do it. But if they don't, they won't change their lifestyle but will probably harbour a nagging feeling that they should be living life differently, or be very critical of the rest of society for not being more family orientated.