Am I over reacting? What to do?

I'm 19yrs of age, my bf is 23, I moved to america to live permanently, only 3mths since I've been here..My boyfriend Lives in South America..He tells me he wants to marry me and heloves me..He made commitments to me, and promise to never flirt and wanted me to promise the same i did..So yes I'm in a long distance relationship, communication is great.I'll be In south america every yr 2 see him...starting from next year.. He told me if I ever flirt with other guys he'll stop trusting me but today i went into his mail and hes telling other girls tat they are very attractive and sending out his email addy to IM with them. Am i OVER REACTING? WHAT SHOULD i DO i'M SO JEALOUS, PLUS THIS LONG DISTANCE THING GOT ME FEELING INSECURE after reading that I am feeling hurt..