Ok, I am going to suggest something which might be difficult for you. But give her a chance to talk. Your recent posts have all mentioned her wanting to 'talk' and you have avoided that. I dont blame you for avoiding that, and I certainly get the notion of protecting yourself with the legal matters. However from what I am reading over the past several days is your W really is confused. Now add that to the discovery she is seeing professional help, it is quite possible she really is having second thoughts but does not know how to approach them, or you. The tax return issue would speak to this as well. She may be withholding them simply to stall, delay, or in some way not want to continue down the path she started.
Now this is all speculation, and I am by no means saying I know this for sure, but give her a chance. Sit down with her, and listen. Listen and validate. I would be cautious of what you say, but give her a chance to speak. However, if she is anything like my W, she will not speak freely. You will have to wrestle and pry it from her even if she is dying to say it.
I also hold off on mentioning how difficult D will be on her or you in the future. You have said it a couple of times, so no need to repeat it. She knows. Was her offer to separate instead of proceed with a D? Your statement of you do not think you can be friends is an emotional one, and I totally get it. I feel the same way at times. But you have kids, young ones at that, which means you and her will be constantly in contact for a very long long time. Even when your kids are grown, you two will be bound. In time, even if you D, a friendship is possible. Time does heal all wounds. It is just hard to see at this juncture.
Again, I do not mean to upset your apple cart. But perhaps extending an olive branch would not be a bad thing the next time she makes an overture at wanting to talk to you. What is the worse that can happen? If it turns out to be a bust for you, well, you still have your summons to answer this week. Best case, things get delayed a bit, and steps are taken in a positive direction.
Me: 42 W: 32 Married 7 years together 8.5 S1: 7 S2:7 Bomb #1: 09-16-13 Recon #1: 11/13 A discovered 04-03-2014 W filed D 05-19-14 but never served me I filed D 12-02-2014 S 05-31-14 Divorced 5-19-16