you are wrong. he wasn't cheating on his gf. he wasn't even aware of his feelings before his gf said "i like someone else too". He asked "What do you mean by me too?" what message are you talking about? Fumi sent a message regarding recipe to Mine by mistake.
i am sorry i replied to your comment by mistake. I was replying to someone else.
to sum it up, the story went something like this -
Year 2011 - Anjou and Mine have become friends.
Around November 2011 - anjou is dating a girl.
January 2012 - his gf realises that he is very close to Mine, that he has feelings for Mine.
Around Feb 2012 - break up. she said "i also like someone else. Indicating that he likes Mine.
Feb to March - He took time to come to terms with his feelings.
March 21, 2012 - He told Mine about his break up. anjou and mine realized they both had feelings with each other. and then after communicating, they started dating.
April to June 2012 - they are officially dating.
Chapter 1 - June 2012 - present.
I'm not even sure I understood what I read