Is it permissible for a husband to ask his wife to watch films that teach about sexual intercourse, and is she allowed to refuse, knowing that he desires this within the bounds of what is permissible (halal)?

Your husband is not permitted to watch films that include scenes of intercourse due to the impermissibility of looking at nakedness, as stated in the noble verse: "Tell the believing men to reduce [some] of their vision and guard their private parts. That is purer for them. Indeed, Allah is Acquainted with what they do." You are not permitted to obey him in this matter, as obedience is only in what is right. Your husband can learn permissible ways of marital intimacy by reading books and research that address these matters within Islamic guidelines.