beta
Yeah so everything was Hayato's fault, because he DID abandon him. That letter was just to say "yeah I'm not going to come, I swear I love you but I'll still get married. I swear it's for you and not because I am a coward who don't want to give up my lifestyle for you."
Touma would have killed himself anyway even if the letter had reached him, because Hayato never chose him.