Hi Horn,
I hope your wife is okay, and that you were able to talk through things.
It is great that you do so much for her daughter, and as a parent I know we do those things because we want to for our kids, and not to have them feel obligated about anything we do.
I have three kids, two of them are teenagers, and there are days they want to be on their own, and want their privacy, I think that is a pretty typical teenage reaction.