I'm on month three. Joining Parents Without Partners has been neat because it gives planned family activities with the kids and some social occasions without them. I can get out of the house (at times forcing myself) and am around people who have been through this AND thrive with their children. I am not alone.
The whole idea of feeding or accepting my dark and light side, my higher and lower self has really helped me in the pressure cooker department. The anger and bitterness I was feeling a few weeks ago was shredding me and hurting the kids. Relieving myself of expectations does wonders. They didn't work anyway so why torture myself?
Setting boundaries and writing down the benefits or cons of different actions slowly lays a foundation of how to handle this whole thing. I have almost no contact with "Kevin", unlike your situation. I could go dark and he'd never know the light was out!
Work on healing yourself, loving and protecting your kids and the rest will follow.
