Hurt And I Need Some Opinions

So my i found a text message on my boyfriend of 10 months, phone. saying when are you coming to visit me with your gorgeous green eyes. and there were a few other words used but i dont remember who said wat him or her. he's never done anything like this before and i can always trust him not to lie or hide anything from me. he came clean about it and said it has only happened this one time and they talk like that to each other because its been like that for years.. i dont know how to feel..do i give him another chance? i love him and he is so nice.. but i am so hurt.. am i over reacting? i want anyones opinion. ... if i truely feel it wont happen again.. should i just let it go and know people make mistakes... he lost his head for a few minutes..right?