I'm in a not dissimilar situation. H doesn't want to be with me, wants to separate, is having an emotional affair that he refuses to stop but won't move out.
I have no legal redress to make him as we jointly own the house. We're sleeping in separate rooms. H still very much leaning on me for emotional support. Our children are teens, but I'd still rather not put them through the stress and disruption of a house move for a few years.
Your h's behaviour is, like my h's, selfish, punitive and cruel. It's very distressing. My h also has no insight into his levels of selfishness.
This training that he's doing... If he's met new people through doing it, I would say that there likely is someone else involved. The woman my DH is having an emotional affair with is someone he met on a course he started a year ago.
All that is keeping me sane is using the children's needs as a guiding light as to what I should do on a day-to-day basis, and trying to 'shrink' him (suggested by someone on MN, consciously stop my thoughts dwelling on him).
Sending solidarity and strength.