mosherose, you must have meant that facetiously. The reason that mixed swimming is assur is because it is kiruv l’arayos. Can you think of a reason why that might not apply to a husband and wife?
Every frum Jew knows that mixed swimming is completely and utterly assur
This knowledge is good. What would be better is if you understood WHY it is assur. If you don’t know the ‘why’ then you’d best not extrapolate.