You didn’t go snooping — you stumbled on this letter and gift accidentally. You should tell your boyfriend what happened and tell him how silly it is that you’re jealous about a girl from 8 years ago, but you can’t help but feel that way! Laugh at yourself because you know that people have relationships from the past that lead them to be able to be where they are now, but also tell him how you feel without putting him on the defense. My guess is that he’ll put you at ease by filling you in on that relationship and why he’s with you — and not anyone else — now.
I hope that helps. Please follow me @AskAprilcom on Twitter. 😀