Because actually, Giganticus, it's not about being a "kept woman" it's about working in a partnership.
If I put it like this, what would you think?
My DH works all the hours in the week, getting up at 6am and often working until 10pm, 7days a week. I'm at home most of the day and if I'm not at home, I'm out shopping or doing other things. Money is not an issue - if I want something, I buy it. I go on weekend breaks when I want, and 2 holidays a year. Makes me sound like a spoiled bitch, right?
My reality, is that DH is a farmer, farming a very large arable/mix farm on his own. He doesn't have time to do the farm admin, because he's too busy doing the practical farming. There is a LOT of legistlative admin, as well as the farm finances/bill paying/booking vets/general office admin etc that needs to be managed, as well as stuff like going to the bank, going to feed suppliers, collecting farm equipment and generally running a business. That's my job. As well as making sure food is on the table so that DH can come in and eat when he's knackered, keeping the house clean, doing the laundry, staying on top of the personal admin and managing the "domestic" animals along with their with vets appointments etc and generally "supporting" DH, so that he can be effective and have a quality of life. Not quite such a spoiled bitch now, eh?
The upside of my lifestyle, is that I can do what I want, when I want. Yesterday, I spent 2 hours playing with my horses. Today I had the time to go to the chiropractor and then go swimming, and tomorrow I am meeting a friend for lunch. Being SAH, doesn't mean that DH works so I don't have to. It means that I have a lifestyle that I enjoy and like and is actually stress free, because I am happy. I suspect that is the same for a lot of SAHM's.