Currently going through a divorce...

While we split on mutual terms, are still good friends & get along, I'm really struggling. We've been separated for almost a year, he has a new fiancé & I have a boyfriend, he is slacking big time on filing the divorce papers. He has them all types up, I've signed & now he's just stopped any progress on them. I don't want a huge fight, but I also want to just be done & move on with my life. I would think he would want to as well! What do I do, to light a fire under him to finish this?