If you were successfully detaching, you wouldn't be analyzing a simple text exchange for signs to how your wife is thinking about the divorce.
It's an exchange between two parents who are behaving like mature adults. It was nice of her to offer you some extra time.
Don't read anything else into it.
Me: 44 H: 44 Kids: 20, 16, 16, and 10 Together/Married: 22 years H announced he was emotionally detached and considering D: 4/4/16 H announced he is going to try to stay and reconnect: 5/1/16