I read up on your sitch and like you I am living with my MLCer. We have two kids. I know how hard it is.
One of the things that has helped me is to try REALLY hard to keep up a PMA (positive mental attitude). First, I have kiddos watching my H act like a teenager so I need to pattern normalcy and offer stability. But also, it has helped me, too. It prevents me from getting drawn into his negative mood and sort of leads me to detach more effectively. I smile when he walks in the door! Try with each interaction to leave him with a positive impression of you. If you falter, brush yourself off and try again.
As for our living sitch, I was advised my my (DB) divorce busting coach to treat my H like a house guest. I think of detaching as compartmentalizing. I am standing but for my own sanity he is my house guest. I often think of him as a visiting relative. This definitely helps me cope better.
Me 41, H 47, M 15 yrs, S11, S13 BD 1: 11/4/14 we work on it; really I pretzel myself BD 2: 3/31/15 H goes down to "dorm room" 8/15: H back to MBR 10/15: H back in dorm room 1/18: H files, now divorced
