So, it upsets you that she was in love with someone else? Can you explain why? Would it be easier for you if she was in love with him, or only in love with him? Or would that make things worse?
As for honor/dishonor....I see that in terms of whether you are treating other people as you'd want them to treat you, and showing care in how your actions will affect others. So, taking the nuclear option and demanding a return to monogamy would be dishonorable, IMO.