Of all the people I asked from all ages, single or married, guy or girl finds that it is not right and acceptable to go out late in the wee hours of the opposite sex when one is attached.

He finds it ok to do so. When I asked if He would be ok if I were to go out with a guy till the wee hours, He said He is fine with that.
Know why He is fine with Me going out till the wee hours with a guy?
He wants to do it. He wants to be able to go out till the wee hours with Her.
He simply wants to satisfy His own desires and totally disregard my feelings.

If He at least care about Me, He wouldn't have said He is ok with Me to be out with another guy till the wee hours.