The Family Laws ordinance

Back in 1958, General (later Field Marshal) Ayub Khan staged a coup and took over the country. He couldn't have made a bigger mistake. As a result of that event, the country was split into two and Pakistan would always be under autocratic rule (even under civilians). One of Ayub Khan's much trumpeted achievements was the promulgation of the Family Laws Ordinance, which prevented a man from taking another wife without his current wife's permission. Now this was not such a major evil that a special law was needed to prevent it. I have so far known only five men who have two wives, although I have no doubt that in the rural areas polygamy is very common. For one thing, no ordinary man can even think of taking a second wife, what with the cost of living going up exponentially after every budget. With feudal lords, of course, this is not a problem, they have all the money they want, and I often wonder why they don't have hundreds of wives (maybe they do, only the "wives" are slave girls).
The thing I find odd about the Family Laws Ordinance is that a man is required to take permission from his wife if he wants to take another one. All mullahs are of course against this law. And the ordinary Muslim would rather kill himself than ask his wife for permission to do anything. I know perfectly normal Muslims who fly into a rage when told that they must ask their wives before they can spend money on snything (like a new car, for instance). It seems Muslims have the divine right to do whatever they want, whether their wives like it or not. As for permission to marry another woman, what if the first wife refuses to give it? The poor woman knows that he'll immediately divorce her (or might even kill her) if she says no. So what's the use of such a law?