I have to say, the author did an awesome job with this stories.
If u think how even if she loved Hikari she did it while still a cat and he loved her as a cat, neither were a romantic love. As a counterbalance, he might not remember her as a cat but they had 10 yrs together since she moved and now hes in love with the girl Suzu instead, while Suzu is starting to feel a different kind of love from what she was used to.