Coffee at Midnight

Kasumi has had a secret crush on Uesugi since high school. Even if he had another girlfriend, as long as he was happy, she was satisfied. After entering university, Kasumi met Miyako, a rather unpleasant barista. He seemed to have the same unrequited feelings for a woman like Kasumi did for Uesugi... The two shared their "unrequited loves," which other people wouldn't understand, and came to sympathize with each other. However, there comes a time when they realized the subtle differences between their respective feelings.

(Source: Kiss Comic, translated)