Scarleteen

I guess I was being a bit nosy and went through some of my boyfriends messages with one of his friends. I wasn't suspicious or looking for anything I was just bored and I read a message from him to his friend saying he thinks he's in love with his co worker, that's probably an over exaggeration because he hardly knows her. More likely its probably just a crush or something but its bothering me and really making me feel like I'm not enough

Well, it sounds like there are two issues here to talk about together, and think through yourself:

1) Acknowledging that you invaded your boyfriend's privacy, and talking about that with him, including taking responsibility for doing that (and I'd suggest not saying "I was just bored," as that doesn't sound much like taking responsibility for something you chose to do without his permission, nor does it make invading someone's privacy okay).
2) Then talking about what you read and how you feel about it.

Mind, I do always like to remind everyone that the idea that any person isn't "enough" because someone has a given set of feelings for someone else is pretty tricky. After all, no one suggests any one child must not be enough if a partner loves more than one child, or a friend isn't enough because someone has more than one friend. Some people suggest romantic or sexual relationships are radically different than those kinds of relationships, but I personally would beg to differ. People in those kinds of relationships can, and often do -- especially over time -- have those feelings for more than one person even if and when they're quite happy being with whoever they are in those kinds of relationships with.