Neo. The Only. The One.
THE ONE
So, to provide an answer that isn't something that assumes absolutes are always true:
People often have relationships that change over time, and looking back either while still angry, or looking back in retrospect, the context of the relationship changes.
There are plenty of people that are completely fine with having children because at the time, they're completely certain that the relationship is strong and will last. But somewhere along the way (sometimes even BECAUSE of the pressures of having children), the relationship falls apart. Then looking back, people realize they were fooling themselves, and were really just fukking around compared to where they are in life now.
Given, this obviously doesn't apply to every single couple that has kids without getting married, but it's definitely a lot more common than you'd think.
I'm not talking about relationships. I'm talking about smashing random hoes and impregnating them.