Munasawagi no Eve

Junichiro Nogi is a serious, stoic yet dull man at work and at home. Satoshi Miyamoto has a beautiful wife, a successful career, yet enjoys his extramarital relationships. Two men, both 40 years old, meet the women of their destinies. Nogi, tired of his job and family, spends time in his friend Asahina's apartment (who is currently away as an expat in a foreign country). He enjoys his alone-time, and manages to decompress there. Suddenly, a beautiful young woman named Ayami Fujimori appears at the apartment and says "Please make me your girlfriend" as she gives him a kiss…!?

(Source: Nihon Bungeisha)