Why is it so rare for a pair of childhood friends to fall in love with each other?

[TipRock]

It seems like it's extremely rare for a teenager or an adult to have romantic feelings for someone that they knew before they were 12 years old. I've never knew a teenage or an adult couple who knew each other since they were small children.

[bunnyhabit]

most girls start puberty around this age so typically don't get into a lover relationship till later like 15+. i suspect it would be very rare for kids to remain with same partnering as they mature and change their perception of mating and personal values for a lover and partner.

i have dated twenty men since i was twelve and my value judgments have changed often

[Anthony]

It rarely occurs, however, there are a few cases where adult couples have been lovers from teenager.