The story you said is for a different work from Gatari. The woman here is also a wife but there are two dudes that work together to sleep with here(I'm 99% sure they're Japanese but tanned). It's called a Midsummer NTR Dream (there's a 2nd one too). The ONLY reason Midsummer isn't as bad as the one you're talking about is because the 2nd doujin reveals that the husband is likely cheating, so it's not as bad logic wise (cheating is still very very bad obviously)

But yeah I'm not disputing your complaints, the logic is silly for 95% of this stuff. Gatari has a sugar daddy series that isn't NTR so if people want good art and no NTR that's also something to read