>How old is your waifus source material, still running?
Touhou Project has been around for two decades already and is still running. It's ZUN's lifework, so it's not going away any time soon.
My waifu first appeared in the 7th installment of the main series, which was released in 2003.
Other than a few cameos in the official mangas, she hasn't appeared since Touhou 13 in 2011.
That's because new Touhou games tend to introduce mostly new characters and Youmu is only a regular guest among the main characters.
But there's a real chance that she might be playable in Touhou 16, because ZUN stated in an interview that he's thinking of using her in the next game instead of Sanae.
>Has the way you imagine your waifu deviated from source material?
Well, I added some headcanon here and there, but the way I imagine her roughly stayed the same. But I can't say that my original perception of her wasn't in part influenced by the fandom. The source material itself is a bit inconsistent and mainstream interpretation of the canon in fanon has some influence on the general perception of a character.
>Has new content (including unofficial) of your waifu been slowing down considerably since she became your waifu?
It has. As for unofficial content: Starting around 2011, a lot of talented content creators have been leaving the Touhou fandom. Then the Kancolle boom happened, bringing the popularity of Touhou to its lowest point in years. Touhou's decline has stabilized in the past two years, but it's still fairly bad compared to the time when I first met my waifu.
As a result, not only the Japanese fandom has suffered, but also the international and Western fandom. Basically, new doujinshi with my waifu are still being produced, but not scanlated.
As for fan art in general, Youmu is still fairly popular, but the overall quality has suffered considerably with a lot of talented artists leaving Touhou behind.
Official content of my waifu and Touhou in general has also been slowing down for two reasons:
1. Rare or insignificant appearances in the main series of Touhou games have led to only few manga cameos in the past few years.
2. Due to Chinese economy, there hasn't been much official merchandise like figurines lately. Until 2013 there has been a new figurine of Youmu coming out every 1-2 years, but none ever since.
>Do you ever hold out hope for a reboot or another series/sequel?
Touhou is always going to be there, for the better or worse.
Compared to most manga or anime characters, Touhou characters are only ever shown in few distinct situations, so I welcome any additional information about my waifu I can get.