All right HH, I am going to dive right in and address some issues in your sitch that stand out to me. I am ignoring what you have previously said about her possibly having been "looking for a reason" to divorce. I will assume that the woman does indeed love you and has been hurt and her ugly behavior lately comes from that pain.
In my honest opinion:
1) Pick a night during the week that you will have the children. Stick to it. This will be hard if she is inclined to call you to take them more or to come over. You will need to tell her no. Again, this is my opinion. Obviously concessions will be made for special events and holidays.
2) Take the kids every other weekend. ONLY. Be it Friday evening til Sunday evening or Saturday morning til Sunday afternoon. Pick the times and stick with them. She whines about being tired on Fridays after a long work week? Tough crap! Join the rest of the population of mothers, lady. Every OTHER weekend you'll get your break, just like all the other single moms, which is what you are choosing to be. I'm tired every Friday too and don't get the night off nor did I EVER seek to. Again, keep in mind this will be hard because of course you want to be with the kids. But it is not about that, it is about making her face reality. And the sooner the better. It is my opinion that you need to assume the same visitation that other fathers get (we're not talking about "fair" here we are talking about what REALLY HAPPENS in MOST divorce cases).
3) The weekends you don't have the kids are YOUR weekends. Get a life and extricate yourself from hers. After all that's what she wants, right? Now to a certain extent, because of the history, yes, you want her to know there are no women in your life. You will have to find a way to do that. I managed to do it by talking to my D10 late on the nights she was with her Dad, and always from the home phone - not my cell - which was in direct contrast to the 8pm calls from my cell in the past after which she did not talk to me again until the following day.
4) Detach. Go dark. She has chosen separation. Now separate. I know this is not easy but lets suppose for the moment that absence does make the heart grow fonder....well then be absent. You see each other at work everyday. That's enough unless you are picking up the kids for a scheduled visit.
5) In case you are doing so, or would be inclined to, don't go over there doing all the yard work, either. My H did that when we separated the first time. I did not appreciate his efforts as I should have. Nope. Not until I found myself pushing an acre of land on a three wheeled lawnmower LAST summer. THAT made me set up and take notice!
Listen, it's harsh and it's a fine line you have to straddle to avoid being called an "arrogant ass" or a "pw shell of a man". You can find it and you CAN straddle it. It is what will make her respect you again. Your very presence has to command it, in humility.
Again though, this is all just my opinion.
Oh! and obviously, leave it ALL at the foot of the cross at the end of the day. Your Redeemer LIVES and cares and wants your marriage restored just as much as you do.
