Please don't go too far with it (it's a free country and it is legal). But it's time for a heart-2-herat discussion with him. Tell him how you feel about it and why you feel so and ask him to stop it. Please take into acount that he might continue watching it.... In that case leave the room and do something else (and say nothing). Don't take it personally, it has nothing to do with you !. Some males do it even if their sex life is wonderful and they truely love their wives. Strang creatures, hey ?