I've always had a problem with that thinking. I agree a marriage is a contract and I believe in a divorce things should be split evenly for large majority of them. However, to expect to live the same lifestyle after the divorce as you did before is just foolish and unrealistic. The household was split in two so their combined income will never be as high.
In most of these cases its the man paying the woman alimony it is up to the man to then pay the difference. What if he loses his job? I know he can go back to court to ask it to be lowered, but a lot of times that doesn't happen. There is/was a very real case of that happening in Flemington where a guy was jailed for failure to pay alimony after he lost his high paying job and after his requests to lower his alimony payments were rejected.
I think the way the way they deal with it post-divorce could definitely be improved. I know someone who was hassled, just like you said, to the point where he was being jailed, which does nothing but make the situation worse. I think men are overwhelmingly handicapped when it comes to making a case that they are being overburdened by alimony or child support payments.
At the same time though, I think, especially when children are involved, the higher paid/more successful partner has a responsibility to maintain a lifestyle across the board for their family.
If you have one parent making good money and another making near nothing, it can really skew how kids feel. How is it fair if one parent can afford to take the kids to places for vacation or see a concert or a sporting event or buy them this toy, but then to have the other parent in a place where doing that would mean taking food off the table?