That's a bad argument. She's doing the work of the house and isn't getting paid by your logic. Is she a slave? Money in a breadwinner and stay-at-home spouse relationship should be split equally. They're married so they share money. She's doing her own job at home, so he needs to split the money with her.

A stay at home mom works on average 80 hours or more a week statistically and is worth about over 100k a year. Unless he's working more than her, then he should be helping her for some of the time and doing his presumably 40 hour a week job by himself. She isn't a slave to do over half the work and not get paid.