He uses the children and this notion of an intact “family” to control you; hold you in limbo via guilt. He knows it’s a sensitive issue of yours and he is manipulating it to the point of extreme emotional abuse. Like YOU are tearing apart the family by not allowing him to live a double life in the basement? Surrrrre.

HE lost the privilege of a family when he threw it in the trash and carried on a 3 year long affair that is still ongoing.
Family is valuable and to be cherished, not exploited to cake eat. Is he acting like a man who has learned this life lesson?

As for some inner work for you, why is it “keeping the family in tact” when it’s all a big lie and he lives having an affair in the same house? Do you value a mere presence more than the real thing? Did your FOO keep up appearances?
It’s not your job to fix his self detonation. Maybe something to discuss in IC.

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