Well, DC, I am sorry you are having it tough today. I think it's good you go dark a bit, just stick to talking about the kids, not you or her. If you have a certain schedule for you to have the kids, stick to it, and don't help her out, don't be her emergency "babysitter". About the friend she left them with, I am sure she loves those kids as much as you do, and wouldn't leave them with a bad person.
And if you date while you are married, you are doing the same thing she is doing; and that's not right.
GAL, do the triathlon training, it sounds great! GAL in other ways, too. Keep your mind off your W and what she is doing. I know it's hard to do, but you have to keep at it.