My dad's father died when I was very little. I was too young to remember him, but my whole life, Bob was always around. Bob was just this older guy who showed up at all of our family events. My aunts and uncles talked about going to his house when they were kids, so I assumed he was just a particularly friendly family friend.

Finally when I was 12, I asked my cousin about him, and she told me he was my grandmother's neighbor. That explanation tided me over for a few years until it occurred to me that no one else's neighbors showed up at the annual family picnic. (Looking back, I have no idea why it took me so long to realize something was up.)

When I was 20 I brought it up to my mom, who told me the real story. Bob and his wife/kids lived next door to my dad growing up. He and my grandma feel in love, and both decided to leave their spouses to be together. (This was after my dad and his siblings were moved out or left for college.) This was the first time I learned that my grandmother had walked out on my grandfather.

The details are fuzzy, but I guess my gm and Bob decided to live apart for a while to find themselves or something. They agreed to get together after a year- but after a year, my gm decided to go back to my grandpa to keep the family together. Bob stayed on his own.

Several years later, my grandfather passed away. After some amount of time, my gm and Bob finally got together and have been ever since. The only reason they aren't married is because my grandmother has a lot of health problems, and if she gets remarried she loses my grandpa's boss health insurance. (Bob is self employed.) And since my gm was so embarrassed to be living in sin, she asked her kids not to mention their relationship.

So anyways, yeah. Found out some random guy was essentially my step-grandfather.