As with NotAllThere, my wife didn't have to pay into any 1st pillar until she went freelance, and even then her payments are low (based on estimated earnings).

My guess is that this applies to people/couples with no income at all from a job. As you have an income and you are a married couple, I don't think the rule quoted by The Finn is valid in this case.

i.e. it applies to no-income families.