I did not see this emphasized, so I’m going to try and say this delicately. Our girls are truly educated to the highest standards of tznius. Part of the experience is downplaying the sensual parts within us and focusing on the spiritual. But the truth is that we are not all that spiritual. Moshe Rabbenu’s wife used to wear makeup at his insistence. Her not wearing makeup was a sign that they had separated. (Yalkut) So without laying blame, but rather with a view towards helping things along, one thing you may want to try is ensuring that his needs are being met. I have known too many couples where this was not the case, unfortunately.
When a kid shows signs of hunger, he is not being fed at home. The same goes for pursuit of Taava on the internet.