She needs to know that although it’s extremely unpleasant, he’s not the first one in the world to fall prey to the taavah. Even if she may not be able to fully understand the taavah, she needs to know that it is a real and tremendously difficult nisayon. She also needs to know that he did not did not get involved because he does not love her nor because of anything to do with her. She should not judge herself thinking, ‘if only I had xyz, he wouldn’t have felt the need to…’. This is his nisayon, and being that she is his partner in kedusha, she needs to stand behind him by doing whatever she can to help him realize his potential and how wonderful he is, because he can overcome this. When she does talk to him she needs to go to him with encouragement and love, and absolutely not with accusation and disrespect.
But she should not talk to a Rav unless she has spoken first to a professional. Very little will make him feel as worthless as knowing that someone else has discussed his biggest struggles (especially something so private) with someone he respects.