I can totally imagine a future Sterek AU when they have a house near the preserve, a dog or two, stable jobs, the pack being a real family and Stiles and Derek having two or three kids that are aged from 8 to 16.
And maybe they have some family evening or the kids are just interested. They look at old pictures and videos in the living room, Stiles and Derek cuddled up on the couch and their kids in front of the couch.
And they start asking why Daddy Stiles is on so few videos and pictures compared to Papa Derek and Derek hadn’t even realized until that point. And Stiles just shrugs, squeezes Derek’s hand and says:
“Well, your Papa had a lot of bad things happen to him and it took a long time before he got over them and became happy again. And I didn’t want to lose any of those happy times, so I tried to capture as many as I could on pictures and videos. And it was really hard, because your Papa doesn’t like me taking pictures of him!”
Don’t let anyone tell you that Derek is the only giant sap in that relationship.