Soshiki no Shukuteki to Kekkon Shitara Mecha Amai

Roushi and Ritsuka once belonged to opposing organizations of people with supernatural powers, and their relationship was one of mutual hatred. After repeated bloody battles, the two are now a loving couple who tell each other "I love you" and never miss a kiss before going out. Roushi is enjoying his happy married life, but is troubled by the fact that he and Ritsuka have not yet been able to perform the important act of a married couple. This is a sweet newlywed comedy about two former enemies. "Yesterday's enemy is today's wife!"

(Source: Natalie, translated)