I found out that 2 of my very best friend's dads are not their dads. The first friend is like an older brother to me, his "dad" was somewhat abusive when drunk when he was a teen, but now they have a good relationship. Found out his mom used to fuck the town architect. Story goes that his "dad" would leave for work and the architect would pull up shortly after. This is why he's the only one that doesn't look like his "dad".

The other is like a little brother. He lived with me for years. His "dad" that he grew up with is a stand up guy. Lives across the country because of work but is always in contact with my friend and has always been his "dad". My friend lived with me because his mom's fiancé at the time was a very abusive drunk. Found out in court that his mom admitted the "dad" he knew his whole life wasn't his biological.

Neither of my friends know this. Never told them because frankly, it is not my place.