I spoke to my therapist about this exact thing. People who D thier spouses to see if this is something they really want. She said it happens all the time. Kind of a test. I too think my XW is doing this to see if she wants to be with me for the rest of her life, so she had to do it. So we can better ourselves first and then see how a R will be later. It sucks, but I truly believe this is a test of our relationship.
In past discussions with the XW, she wanted to do a 2-3 year trial seperation. She has also said, We need to take this time to do things for ourselves. Which I found contradictory, since one of our biggest problems was we never spent to much time together. Less time after the D2 was born.