The swallow which I loved

The first time he saw him, Wakana was fascinated. Swallows heard from others are rumored to be "mistresses." "It wasn't for me." He was from another world. The more he talks, the more he feels worried about his laughing face and the more nervous he feels. However, the relationship between the "mistress" that can be glimpsed from the swallow makes Wakana's heart jealous ...?!? Note: Chapter counts include an extra chapter.