rewatched Becoming Part 2. You cannot tell me they weren’t setting up Spuffy from the very beginning. It’s right there in they’re entire shared interaction. And it all ties beautifully into their future dynamic. But what gets me is her right before being told she is all she has and will forever be alone and Spike being the first one to be there afterwards being like, i’m all you got, i’m here to help, i want to help save the world. And this does not change throughout the rest of the series. Through the rest of the show he continues to be the only person who CONSTANTLY has Buffy’s back; specifically paralleling season 7 when Buffy is at her most isolated both emotionally and physically, and Spike is still there, the only person she still truly has in her corner.