Im so heart broken</3?

i love my girlfriend and she loves me. but she moved acouple months ago and i havent seen her in 2months. only messaging. she tellls me she loves me and that she wont cheaton my but i know she is. so i know this is wrong but i checked her email and it had messages from this one girl she used to kick it to. and they where talking about meeting up. and doing stuff:/ but the girl would be like oh dont u have a girl and she would say yes i do and i love her but i want to see u. :( and the worst part is that i cant tell her anything cuz i dnt want her to get mad that i checked her mail. and well this girl whose been talking to her is trying to be my friend now and i kinda like her but then i think about the messages and i just wanna kill her! no jk but i get really mad and i wish shed trip or something. well but i really love this gir; and idk.. idk theres really no questin i guess but any advice?