Japanese TV, the law, and divorce

As I am writing a  Japanese TV show in which situations are presented (dramatically acted out, of course) and a panel of legal experts decides whether certain courses of action are legal or not.  The results are often shocking.

One of today’s skits featured a woman whose husband kept asking her about her past boyfriends/sexual partners.  He wanted to know how many men, what they were like, what she liked about them, why they broke up, etc.  The woman was shocked by these questions are absolutely refused to answer them.  Her husband would pester her constantly with the same questions, and she continued to her refusal to answer them.

What did the husband do?  He hired a private investigator to discover her dating/sexual past.  After he found out who her past boyfriends were, he tried to approach them all and interview them about the details of their relations with his wife.  Eventually his wife discovered photos of her ex-boyfriends in her husband’s stuff and confronted him about it.  He told her what he had done and explained he had only done it because he cared about her so much that he wanted to know everything about her.  Since she wouldn’t answer his questions, he had to find out the answers himself.  Her response:  Divorce!!!

Would the following situation provide legal grounds for a divorce?  Only half the panel of legal experts thought it would.  The other half thought that since the husband had the good intention of wanting to know more about her, it would be unreasonable to divorce him for just going a little too far.   It was clearly her fault for not answering her husband’s questions.  After all, she could have just given him a fake answer to the question.  The final conclusion of the show: it would be legally difficult for her to divorce her husband using the above situation as the reason.
I assume that she would still be able to divorce him, but she wouldn’t be allowed to provide the above situation as some sort of legal proof that the divorce was her husband’s fault.  At least I hope so.  Either way, its fucked up.