Antonia, I don't know whether you recall we started a dialgoue about whether your h was in full MLC or a life crisis transition? And someone intervened, and said it didn't matter. I was busy, and didn't want to go the argumentative route, and dropped it. Anyway, from this conversation, I am still not sure that your h is in full blown MLC. Compared with my husband [actually my ex-husband now] he is pretty human.
But he is still a very messed up human being and you are internalising his point of view. Most of us do this. We empathise, and see their point of view. He is having a 'blame externalities', take no personal responsibility, and pity party instead of facing up to who he is and the cowards way out he took from a difficult relationship.
Marriages hit bad times, and we have the opportunity to grow through that. You clearly had issues as a couple, and from various postings it sounds like your h has a lot of unresolved problems. It is possible that this woman can accommodate them, but it will be at great cost to herself. Let him go for now as far as you can. Until he sorts himself out and stops behaving like a spoilt teenager for whom life hasn't measured up to his expectations, you are better off without him. You can grow unaided, and have a good life. The suffering, horrible though it is, strengthens us.
Sadly we live in a society which validates people walking out of their marriages instead of working on them. Your husband's self esteem, too fragile to cope with your being more successful than him, is boosted by a younger woman who appears a success in ways that do not threaten him. Take away your support from him, emotionally remove yourself gently from his life. Deal with the cats yourself. When they leave us, they have to understand they have left, and that is their choice, and live with the consequences.
Less texting, no more gifts. Cool and dark from now on, for your sake.