I agree with Labug. It is tricky with the kids. Mine are so so young, they don't get it at all. But, I know for me, a schedule is helping. It doesn't have to be permanant, but I needed some space to work through my own emotions and it is just too hard for me to be around H too much.
I have nothing to say about his living situation. It's hurtful and crazy, but it is what he has decided to do. He's a jerk, but you can't stop him. I would, however, ask him nicely to stop talking about OW with you. I had to do that when my H was with OW and would try to tell me how awful she felt. Well, not awful enought to stop sleeping with my H... I calmly said, "Look, I really can't hear about her anymore. It's very hurtful."
Good luck!
M: 9 yrs T: 13 yrs H:34 Me:35, S4, D2, S 7 months Dday 11/12-PA & multiple PAs Dbing 12/12 S 1/13 7/13 H moved back in basement. 8/13 #3 born 10/13 still cheating 10/13 He moves across country, I file for D