Aisuru Tsuma no Netorase Houkoku -Gyaru Tsuma Ria no Baai-

Masato has admired Ria since he met her in college. She has excellent communication skills, is cheerful and kind, and was the first woman he truly loved. His feelings were reciprocated, and they have stayed ever since. And every day spent with his beloved wife was nothing short of blissful. However, the happier he felt, the more shadows fell on Masato's heart. He started doubting if Ria and him were a good match. He thought that perhaps there was a man more suitable for Ria. His feelings became twisted, awakening a cuckolding fetish that further deepened his troubles. --But upon learning of his feelings, Ria said, "If you want me to do it, then let's do it... I'll cheat on you" [From the translator's Discord]