What is she gaining by legally separating as opposed to D?
In New York, a legal separation document can be used as a framework for the divorce settlement after one year. So by having a legal separation agreement in place - in addition to having a legal document forcing us to a certain budget and certain rules of spending - you can avoid a painful, protracted, and contentious divorce process if that's what you decide to do.
It's only enforceable a year after the document is signed and notarized, so she can't just turn around and D on those terms. If either one of us in the months before that decides that D is what we want, we'd go through the process as if that separation document didn't exist.
Optimistically, she gets a legal document that organizes our spending, which has long been a concern of hers. And it's a way for her to understand what the ramifications of D would be without having to be fully ready to make that decision.
Pessimistically, it's a way of having discussions about separating assets while there's still a glimmer of hope, as opposed to during the D process when it's not likely to be as amicable.
