Is it permissible for a husband and wife to bathe together and look at each other's 'awrah (private parts)? And is it true that the room must be completely dark and some clothes worn during intercourse?

It is permissible for spouses to look at each other's entire body without restriction, based on the Almighty's saying: ﴿And those who guard their private parts. Except from their wives or those their right hands possess, for indeed, they are not to be blamed. But whoever seeks beyond that, then those are the transgressors.﴾ This is supported by Al-Bukhari's narration from Aisha, may Allah be pleased with her, that she and the Prophet, peace and blessings be upon him, used to bathe from a single vessel, as Al-Dawudi used it as evidence for the permissibility of a man looking at his wife's private parts and vice versa. As for what is attributed to the Prophet, peace and blessings be upon him, regarding the disapproval of a man looking at his wife's private parts because it causes blindness or muteness, it is a fabricated hadith and not authentic from him.