Boku wa Ai wo Shoumei Shiyou to Omou.

Technology wins in all matters of romance and love. Let me teach you the ultimate technology to captivate women, "Love Engineering"! Watanabe, a 26-year-old patent attorney, is shocked when his beloved girlfriend Maiko cheats on him. He is depressed by the reality that nothing is going well and drowns himself in alcohol at a bar. Then, suddenly, Nagasawa, whom he met at work, appears and he witnesses him captivating a beautiful woman on their first meeting in an instant! Nagasawa tells Watanabe, who is chasing him, about the existence of the ultimate technology to be popular.

(Source: Kodansha, translated)