Also I like too ad Sasuke has no sister parallel to Sakura. I know naruto is his brother replacement and kakashi is the father.
Sakura is the mother but since she is his age, she could also be the wife. And Sasuke Imo is more about parallels than Naruto is.
"is like a family to me" doesn't mean everyone has to have an specific role like father, brother, sister, wife, aunt, grandmother and stuff. It means he felt family love for them. The love one has towards a wife is both romantic and familiar, but he didn't mention any kind of romantic love so only the familiar one applies, so if you want to attribute a role to Sakura as a relative, she would be like a little annoying sister or cousin to Sasuke.
And are you really serious that Sasuke would ever think of Sakura as a... wife? I mean, really? What the hell...
Bonus: do you want me to say what SS needs to melt down?
- Nothing, it's ruined already.