Great that you have taken steps to meet with a lawyer and informed the OBS! Well done on taking the first steps on the journey to get out of infidelity.
We all know that momentum, once lost, is difficult to get back again, so keep yourself motivated. Don't look at the end of your M as a bad thing. If your WW is truly remorseful, who knows? You could get back together a few years after the D. Life does not end at the end of a M.
Start the D process. Go through with it to the end if required, but the end goal is to get you out of the sh*tty situation you are in now. Yes, it will cost money, but money can be earned back, whilst you only have one life (unless you are Buddhist, then that is s different matter altogether). Don't squander your life away, thinking and worrying about things that don't add well-being to your life. You might think that your WW does that for you, then think hard about it. If she really does that for you, you would not be here now.
The worst thing you can do is to get yourself in to a hand-wringing state. Worrying about everything, and making yourself anxious.
Get yourself calm, and go look up the OODA loop (thanks to another poster here, LtCdrLost, for that nugget of info). Use it to make sense of your situation. OODA stands for Observe, Orientate, Decide, Act, and can be used for a variety of situations. You will need to be calm to make sound decisions, for your own sake, and for the sake of your children.
BTW, I do hope that you have started implementing the 180. Businesslike communications. Only talk about finances and your kids requirements. Treat your WW as a work colleague, so no hugs, no kisses, no emotional stuff.
Also, as Hellfire suggested, go get yourself a Voice Activated Recorder, and keep it on you at all times. From what you have posted, it looks like your WW is deep into lala land, and could lash out verbally, and could accuse you for ruining her dream to be with her OM.... which, I must admit, you have..... but if their lurve is so strong, it will overcome this hiccup
ETA: It looks like you are the one doing all the work for this so-called R. Sorry to break it to you, but if the WW is not doing any of the hard work to R, then you don't have a R. If R is a path you want to explore, then WW must have ownership of the process, otherwise, you will be wasting your time.
[This message edited by RocketRaccoon at 9:13 PM, November 13th (Tuesday)]