I'm also for Rintaro in this story, but this 10th ep let me the bad feeling it would be Hiroto after all.
I do agree with Boutux about Rintaro's behaviour, it's just disappointing to see him act like that. I think it doesn't fit with his character in the previous episodes.
Though the beginning of the show was great, I lost interest all along, and I think I will finish it just because I want to know what will happen, but not with great desire nor pleasure too. I was not able to really like the characters, though this kind of story should have interested me. I really really really don't like love triangles.