Why do some divorce laws involving alimony include the statement "to maintain the lifestyle he/she has become accustom to"?

Why shouldn't a woman who agreed with her husband's request for her to leave the workforce 10 years ago, so that he could focus on his career while she would focus on the kids, get the same financial rewards that the husband gets, or at least somewhat comparable?

If the couple agreed that the wife would give up work for their two children, and gave up furthering her education so that he could further his, why should she have to suddenly struggle?

When your husband tells you, repeatedly, "There is no need for you to drive all the way to take classes, you won't be home in time for the kids. I make plenty of money, wait until later in life." and you believe him because you have never had a divorce in your family what are you supposed to do when you have a suprise divorce thrown at you from literally out of the blue?

If for over a decade, you have no reason not to believe that your husband means it when he says "I would never leave you. You do as much for this family as my job does.", what are you supposed to do, when you can make, at best $12 and hour, and that is generous in this economy, while he has gone from $16k per year when the marriage began, to over $130K in ten years time? He worked hard to get there, but who fed him, who made sure his kids were award winning honor students, who made sure he had clean clothes ready each morning, who gave him advice that paid off, and who took care of him when he was sick; the list goes on and on...

Now say that for a small time, when the kids were both in school, you attempt to go back to school, and take out student loans that he said he would pay. Something happens half way through school, due to HIS family, and you are forced to quit. Circumstances change and you cannot go back anytime in the foreseeable future. What if you found out he was just tossing your student loan bills, and now you are in default? Even if you could find a way to get money and go to school, you would need to pay out of pocket.

Now say one day, you are told, "I'm ready to move on. I will pay the house payment for you and the kids for one year, and let you have your car." When you freak out, because you don't know how you will take over a mortgage in one year when there is no one there to listen to you, cook for you or the kids, etc; so you reply "No, that is not fair." and then you are told that he has the best attorney, and he is unwilling to pay for you to have your own, and if you try to contest, he will make sure you have nothing. No car. Nothing but the minimum child support, and if I make it difficult, he will take the kids. You have no money because you trusted and loved and believed. You don't have a cent for your own attorney.

Would you have to ask about this law if this happened to you? Your mother?