I can lay claim to TWO marriages & no kids - vasectomy.
The first was a polite way of leaving home. The legal age was 21. I got married 3 months after. My second was at age 27 (???). I can lay claim that I made the same mistake twice - both Poms (555). The second one even suggested that attending AA would be a good idea.
Many, too many shack-ups.
My current partner (whom I choose to call my wife) was 24 (now 37). She wanted marriage but I sat with her & explained that a formal marriage means little in this day and age. I have suggested marriage a few times since but she states that she is happy as it is.