Lana, immediately after I saw this I wrote a long post which disappeared in the vapors. Keep in mind that these are my thoughts and you ultimately have to decide what is best for you and the girls. Also, I'm going to pose some questions to you. They are meant to be something for you to think about if you do talk to him.
I see conflict here. Are you really done? Do you really want a D? If not, I would not risk "stirring the pot." I always warn my clients about the danger of bluffing. Never threaten something you do not intend to follow through with. If you are ready for D then you won't worry about him taking offense to anything you ask.
Back to those questions, again for your thoughts.
1. You don't ask if there is or has been another woman. Does that matter to you? Would it make a difference in your plans. Do you think he would be truthful about it?
2. I would most want to know what his intentions are with respect to the girls. As I understand it, he pays nothing for them and hasn't seen them in a long while. Golf is an expensive hobby. It is hard to win tournaments if you aren't practicing. Why would that money not be better spent on the care of his children. What are his plans with respect to visitation? Has he considered the impact his absence without explanation is having on them?
3. Is there truly no benefit to you either way for a divorce. If he pays you nothing, he offers no help, he won't even respond to your request to call (which only under threat did he respond to with a TEXT), what is there to hold onto? Is it the belief that he may come back a reformed man? I think you have an idea where that is likely to turn out.
4. What would you gain in a divorce? Would it help you let go? Would it give you peace of mind? Are there religious or moral imperatives for you?
Have you done 25's mental exercise of imagining that he died a year ago and wondering where you would like to be now? If you are in the same place, there is probably no harm in hanging around. If not, then you need to consider the divorce, or at a minimum what you are doing for yourself right now.
I think every day now about what I can do to move this thing to fruition. I want to be done. I hate limbo. My L says do nothing (but keep in mind that mine is paying me substantially more than the amount we have tentatively agreed on). Have you talked to a lawyer? Have you considered what is best for you from an emotional and financial position.
Just some thoughts that occurred to me from your post. Know that I am pulling for you whatever you decide.