Well, gosh, there have been so many replies! Some have really touched me - the support and understanding here is incredible. Some have been from people visiting from the 1950s, but hopefully their stay will be short :-/ (Moopsboops springs to mind, among a couple of others).
I feel I should report back. I didn't go on my retreat (don't groan!). DH had hurt his back a couple of days before, but had said to me it was fine for me to still go, etc. The night of his unfortunate comment to me, I watched him go down the path of the back garden and saw how he was walking - slowly and bent double. I decided despite his cockery by making that comment, I couldn't leave him having to lift a heavy toddler in and out of cot/highchair/buggy, and I cancelled the course (but I am rescheduled to go at the end of October so it is not all bad!). When I told him of my decision, he was sooooo relieved and told me how awful his back had been and that he was fearful it was a slipped disc but hadn't told me how bad and had tried to act normal (remember, I was barely seeing him as he left early and was back 10-11pm each night), because he didn't want me to miss my self-care weekend. Well, I took him to the physio the next day and he had treatments and acupuncture and it is STILL pretty bad. He even didn't go to work on Friday, which is pretty incredible for him. And there was love in that and that helped me put the comment to one side. The people who said not to load that one comment with too much import were perfectly right.
Sooooo, in that climate, I think the comment should be ignored. For those enquiring, at the time I said 'that is really disrespectful of my role' and he said 'I'm sorry'. I said 'You should be' and went upstairs to bed, where I lay awake thinking about what it all meant.
I do suffer from depression and low self-esteem (goes back to years of bullying at school), and some of the comments of support on here brought me to tears. I don't place enough importance on my own role, and in some ways I think he takes his cue from that. We are at Relate (again), and there are lingering issues of resentment on his part at my changing my mind about going to NY. But I was in a really really dark place then (I was on medication and having CBT on the NHS), and I think people saying I was selfish not to go are just absurd. I have to survive too. I have to keep my head above water, for the kids as well as for myself, and if the move to NY was too much for me, then I did the right thing. I am amazed at people who said I wrecked my marriage, etc. It was a constantly changing situation, and I decided a certain point that it was the wrong thing for me and I was clear from then on that it wasn't going to happen.
As it happens, the move is back on the table, and now that my youngest is a little older and I am a little stronger, it is now a possibility that doesn't make me feel sick with fear.
For those enquiring about the course - it is Vipassana, which is a non-religious course teaching mindfulness and the art of living. Unfortunately, you have to do a mothership of a 10-day course first (which I did while young free and single and living in Japan - nearly killed me! 4am starts, no talking, no reading, no music, no phones), after which you are entitled to do the 3-day 'old' students course. I haven't meditated since, but I really feel the answer to my depression and self-esteem/negativity issues lies within it. So I want to have another go, and I will. I am sure there are other, less hardcore courses available (the hardcore bit appeals to me, but then I am the woman who went from doing no exercise to a five-day residential Marine bootcamp! - and back to no exercise again :-/), but Vipassana is one of the best.
Thank you so much to everyone who took the time to reply here. It definitely taps into the great divide between the parents who work full-time and the parents who don't, and how hard it is to understand each other's role. It has given me much to think about, and so many people got right to the heart of the problem with very little go on. There are truly some amazing women on here.