Calling it something like unemployment benefits is a cute line, but a busted analogy. The child rearing did not produce income, but it does cost money. It's an expense which should be shared equally until the children are over 18 absolutely, and the number of hours spent caring for the children should be equally and highly valued. Child support is a different matter entirely. I think alimony by definition is not child support?
Now once the kids are grown a bit, perhaps your skills are now somewhat obsolete. Once the kids are in school full time, 5-6 years old, how many at that point are actually staying at home?
Even if a person is just starting a career, how many years into it does it take to get established? 2-3 years you can get started in almost any industry. Don't tell me the stay-at-home partner just really wanted to be a Doctor and they should be funded to go to that now. So I can absolutely see paying for 2-3 years if the income is there, and it's needed for the ex to get started in their new life.
The best thing for these laws will be gay marriage. When it's two same-sex partners being judged, how the decision making might be surprisingly rational!
1) You don't get unemployment benefits for life. There is usually a limit. It is a free ride.
2) Women today expect men to share work at home equally. Not every couple does that but many do and most women do return to their jobs a few years after child birth. So what exactly should the women be reimbursed for?
Now, implementations vary, it's often hard to know facts about the life of the marriage and there are certainly many biases affecting judgment, but the core idea is definitively feminist: fixing an injustice that overwhelmingly affects women in a gender-equitable way (both men and women should get alimony if they fulfill the conditions).