Mrs. Him does not mean that I can't be Me, short of breaking off the engagement. Dear Mrs., I do have some. Break off the engagement. It's a formula for more misery than you would believe. Learning about the mate is what engagements are for, and you shouldn't ignore what you find out.
Constant argument is a terrible, terrible sign.
It predicts nothing good. Please put this relationship out of its misery and find someone you feel cheerful and funny and free with. Life is short. Don't enlist in the Thirty Years' War. The sight of her shivering at the bus stop every morning is upsetting.