So yesterday my boyfriend's phone went off while he was in the shower. I looked at the screen and said he had a new message, I opened it since that's what I normally do when he gets a text or a call and ask if he wants me to reply or answer the phone call. Anyway, I noticed that the message was from this girl who he dated a few years ago. Before I could let him know he had a text, i noticed a message from him to her saying that he liked her but that it was wrong and that he shouldn't because of certain reasons (the main one being he is with me). It left me very upset and I didn't tell him I saw that text.. I don't know what to do. He says he loves me and that he would never leave me, but it hurts me to know that he even sent that to her. What should I do?