Sam decided to quit hunting shortly after the Winchesters found the demon that killed Mary. John, not so driven by revenge, allowed his son to go back to college and finish his law degree. The youngest brother was still hurting from losing his girlfriend Jess, so it took him a while to open his heart again to love. Eventually, he managed to find a girl he liked and married her. Given that he and Dean decided to move into the same neighborhood with their respective families, it was bound that you would spend some time with him and his wife. You don't have a problem with this whatsoever, but considering the request of your brother-in-law to not tell her about the supernatural, sometimes conversations were difficult. Thus, you're only glad when your nephew comes running down the corridor to take his mother off your back. You really cannot keep lying to her about made-up stories of Sam's past.

Shortly after she's gone, Dean comes to you. "Having a hard time, Sugar?"

You sigh, "yeah, she keeps asking about the scar on his arm, and I don't know how to tell her that a werewolf almost killed him that time."

Dean hums, "Sammy really doesn't want her to know... I'm just glad you know where all of my scars come from."

You are too. Even though you understand Sam's decision, you can't imagine having to lie to Dean about your past. After all, you are who you are because of it, and you wouldn't have it any other way.