I feel sorry for the op. I don't think that, if there's the money for it and - here's the clincher - her husband doesn't carry his share of hour-round-trip school runs, walking the dog, ironing his own shirts, mowing the lawn, or cleaning the bathroom (and I suspect he never has), why shouldn't she get paid help? Otherwise she would be doing ALL of the drudge work, and, reading back, these are not full-time helpers, so she is still doing the vast majority of work maintaining the household. That is their norm, and it has been by agreement. I'm not surprised she fears manipulation in suddenly being asked to look for work.
I also think she WNBU to say to her dh (once) 'given you are senior enough to have the flexibility to do so can today be one of your work from home days, as ds is poorly, and I don't want to miss my course?'
I am also uncomfortable with his signal that the OW with whom he has had a lengthy affair is a better person for having continued in her career, drawing an obvious comparison with the op.
The op is understandably stung by the unfairness of what she considered to be a lifestyle accepted by BOTH partners now leaving her insecure and fearful. I recognise the powerlessness of someone who adopted BY AGREEMENT the home-keeper role for years, then finds herself critiqued by her oh (and many posters here) as privileged, entitled, spoilt, precious, stubborn, etc. I don't think she set out to carve out a life as a mumsy son-doting layabout with a cadre of paid help. If I were the op, I too would be extremely cautious for my future.
The absence of sex thing .. well, I don't know. The marriage sounds terminal to me. But it certainly sounds like the dh is putting an exit plan in place. Be prepared, op.