His Secret Office Romance Partner is Me. Extra Edition

Salesman Ayakawa and designer Yamagishi are notorious for their constant bickering at work! One day, Ayakawa hears from a junior colleague that Yamagishi is in an office romance—and it instantly puts him in a foul mood. After all, he is the one dating Yamagishi! Behind closed doors, the two are actually a sweet and affectionate couple. What happens when their secret office romance comes into play? (Source: Core Magazine, translated) *Note: Includes an extra.*

*Note: Includes "Shanai Renai no Aite wa Ore desu kedo? Bangai-hen (社内恋愛の相手は俺ですけど？ 番外編)" and one extra chapter.*