I do not know what exactly you mean by "resolving the situation", but the general advice I can give for a case when face-to-face oral communication does not work is to write a letter. Organize your thoughts well, plan it well, do not rush it, etc.

The next step if written communication does not reach its intended goals is couples counseling in which a third party who is a professional helps the two partners communicate. The professional should not take sides but rather facilitate communication. If the professional takes sides rather than acts as a neutral facilitator, he/she should be fired ASAP before further damage is done.