My ex and I both grew up in the south-east. Knew each other from the age of 11. When DS (12) was born, we were some 10 years out of school and had, obviously, both known each other's families for years.
My mother had met his mother, my father had met his father. However. My mother and his father hadn't met until DD (20) was 9 and DS was 1, for various reasons (his father worked abroad, my mother can be somewhat difficult). When they did meet... it turned out that not only had they both grown up in the same Midlands/Welsh border town and known each other, but that they'd also dated/been engaged for a while - and she'd dumped him for my father! Perhaps needless to say, they both now like to pretend that the other doesn't exist, but... well. If they'd stayed together, then neither I or my ex would ever have existed, and our children certainly wouldn't have!
My parents were both born in the same area, too... but met in Germany, where they were both stationed with their separate Army units. My paternal grandfather also knew my maternal grandmother's sister. Intimately, shall we say? Whilst married to my paternal grandmother (she then divorced him and moved to the south-east).
I like to think that these coincidences simply mean that my children were both meant to be and that, for whatever reason, my ex and I were being pulled together to create them.