Bijo to Chinjuu

It's about these two veterinarians, Shuu and Katsuki, who love animals very much. They have been a couple for many years, and friends before that. It is their love for animals that brought them together and has kept them together. There are three chapter, the first shows them as adults, the middle when they were in school and how they met, and the third is the more about them as adults. Even though they have been together so long what will Shuu do when he finds out that Katsuki has been approached by a school friend to open a veterinary with him?