I think it's also:

3) They dislike working and want her to suffer along with them out of solidarity/fairness.

4) They are completely unaware of how much more sleep and leisure single women (including mothers!) have, and how much women like self-directing their lives, so they don't realize that their wife is missing out on anything.

5) Worrying about female infidelity (not unfounded, particularly if he is away a lot).

6) Worrying that she'd spend all of the money on shopping and spas (makes sense, if she does a lot of spending while working, she might not stop merely because the income is lower).

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I think we underestimate how many men see their wife's employer primarily as a sort of adult babysitter, rather than a source of income.

And I think college is an alternative way that women fulfill #3, as it's tedious to sit in lectures and write exams, so she isn't "relaxing or having fun" during that time.
So, women who find working difficult because their families move around a lot or their husbands have demanding hours, etc. can use that as their fallback "We Are Suffering As A Team, Everyone Is Struggling" option.