I bet if your husband had gone shopping with you and been the one to spot the dress and 'choose' it, he would have loved it. Like everybody else is saying, it sounds like he is saying these things to give him control over you.
Have you ever said anything about his clothes to him - what do you think he would say if you just randomly criticised what he was wearing or had just bought? Might be worth trying one day just to see his reaction. And then if he accepts your comments graciously - fine. If he goes off on one about how he knows he looks fine, then if he ever passes comments like this against you again, try his response back at him and see how he likes it.
Might also be worth practising some stock comments to come out with at these sort of moments to give you confidence and not let him bully you. Things like 'The shirt has been ironed beautifully (assuming it isn't really creasy!) but if it's not good enough for you then iron it yourself and show me how you like it done. I'm not your ironing slave'. Or 'Are our daughters and I not allowed to have our own opinions any more?' Or 'Who voted you to be dictator in charge? I thought you wanted a wife when we got married, not a slave'. Or just 'that's just your opinon - what a mean and nasty thing to say to me' when he is priding himself on being 'honest', 'factual' and 'truthful'
However one of the things that worries me most about your post is the fact that you say that you are not fat - but if medical opinions are saying you should weigh a little more then chances are you are not even normal or slim but on the underweight side of things. If your husband is suggesting that you should go against medical advice (I realise I'm extrapolating here from your posts - sorry if I'm wrong) and stay the weight you are or lose more then that is worrying on so many levels.
What would he say if you were to sit down one day and say to him that you are worried about him working so hard, that money is not the only thing in life, be better to have less money and more time together, you hate just being a domestic skivvy, you want you to both share the responsibility of running the household together... I think he would be horrified - it sounds like he has got everything just the way he likes it and everybody looking after him. But it might make him realise that you are not going to take it for too much longer and that he does need to change.
YOu are the one that says you are in a cage - cage is still a cage whether or not it is gilded. and as others have said, what would you do if you thought your daughters were in the same position?
And remember that MN is here to support you and provide the honest opinions - be it on clothes or his behaviour, they don't have any other agenda like he does (ie keeping his nice life)
Start wearing your dress again. It's good that it can't go back. Reclaim it as the first step to unlocking your gilded cage - you KNOW you look good in it - you didn't need your dds to tell you but they did anyway because they are honest and love you. And even though this is an AIBU thread, pretty much everybody is in agreement that YANBU - but your dh is. So wear the dress and think of it as armour imbued with the strength and wisdom of your dds and MN because every time you do, you will be showing your husband that he can't control you. And if he makes any nasty remarks about it again, just blow them off with a 'funny, I've had so many positive comments about how good I look in this dress (you have on here!), seems this time you're the only one that doesn't like it' and use it to build up strength and courage to start getting your life back to what you want it to be.
Now go and put the dress on!