After the divorce, you and your ex-spouse will have two separate households. You will have to maintain those two homes on the money with which you maintained one earlier. “Two” cannot live as cheaply as “one,” especially when “two” are two separate households.
Furthermore, if your ex-spouse has been a jerk all of his or her life, it is very unlikely that going through a divorce will make him or her less of a jerk. A drunken wastrel will probably continue to be a drunken wastrel, and nothing the court nor I can do will be likely to cure the problem. After the divorce, you will be separated; but to the extent that you are still tied together by visitation, child support, alimony, or debt payments, you will still have to deal with the problems together.
If your ex-spouse-to-be is garbage, then no matter how hard we try or how well we succeed in court, your ex-spouse-to-be will probably still be garbage.