In one sentence, they're toxic! Kiyoi doesn't deserve Hira. Hira is too good for kiyoi. Kayoma is the Hira should be with. He is the only one that treated Hira right.

Kiyoi never loved Hira, he just loved the attention he got! They both were mentally fucked up! He was just searching for the attention he never got from his parents. He thought Hira was selfish because he never asked how he felt! But he's the one who never thought how his behaviour is hurting Hira. Even he badmouthed about him to his co actor.

On the other hand, Hira had no self respect! Kiyoi treated him like shit still he kept giving! He probably loves hurting himself! If this is love, then it's better to stay away from it!

The only person loveable here is Koyoma! He really cared about Hira and even after being rejected, he thought about his happiness! Hira and koyoma would make a great couple!