Kuro, Oyome-san yo

Every day, the stoic black cat, Kuro, diligently follows his perfect routine and enjoys a carefree single life under his owner's care. Despite living a life devoid of sexual desires, Kuro has no complaints. However, his owner worries that he might be lonely and decides to find him a wife. But on a stormy night, instead of a bride, Kuro encounters a cheeky and carefree younger stray cat named Mike.

(Source: Takeshobo, translated)

Note: Includes an extra chapter.