None of us ever knew where our journey we never asked for would take us. Even when we think we have finally learned, we hit a fork in the road. We see signs telling us to turn left and then find signs saying road closed ... detour. New journey. How many miles to go? We just never know.
This may be a major change in direction for you. It may not be the end of the journey, but a new route you must take for now. What you do with what you have now been told is up to you at this point. You have seen many threads where the WAS thinks they know what they want, and then flip right back.
Not trying to say to stand. No one can tell you when to do so, or for how long. Just saying if he wants a D, and a new life with GF ... it is your choice right now to file or force him to step up. I won't say "man up" as in this case it does not seem to fit.
Or you can prepare to shed any doubt or blame you may think others will lay upon you, and bring this to an end. It takes two to make a M. One alone can't make it happen. One alone can destroy it. One alone may do what is needed to begin the painful closure.
Yes, it is and will continue to be painful longer than you ever suspected. It will linger and sneak up on you often. And then, after some time passes, it will do so less often and with less impact each time. The detaching you learned during the years of limbo will need to be redirected to the D if one is filed. It does not need to be a judgement of your M, just a change in direction to an undiscovered destination that you are now better prepared to treasure when you find it.