beta
The people who are saying that Taichi shouldn't have been with Chihaya are the same people that were blind to all the effort Taichi has made to keep Chihaya happy.
Tai didn't even want to play karuta again but he joined the club to make chihaya's dream come true. He didn't want to give Arata's phone# to Chi but he still did because he cares more about how she feels than his own self. Have you not seen? That everytime Chihaya was having a rough time the person by her side was Taichi? Arata was never going to someone romantic to Chihaya, the longing that he felt for him was that of a comrade, a rival and someone to enjoy karuta with.
Chihaya (even though she didn't mean to) has disregarded Taichi's feelings, effort and just everything that he did for her and that's why on S3 episode 24 she called herself "I'm the rock" she was the rock that couldn't notice just how much Taichi cared.
I say that this is for the best. Chihaya needs someone like Taichi that will balance her life rather that Arata.