Realationship trouble??

My boyfriend use to be obssesed with this girl who is one of his
best friends. They talk all the time and the send eachother messages about how they love and miss eachother so much.
I know they say their just friends but
I'm still kind of jealous. My boyfriend is a BIG flirt. He is always hanging around girls
and now that I'm 5000 miles away from him I'm unsure of things right
now. I guess I'm jealous and unsure of our realationship.

What should I do?

If you can't trust him then why are you in a relationship with him. Has he ever given you a reason not to trust him or are you just afraid of what COULD be ? These are questions you need to ask yourself. Also how long were you together before you became seperated by so many miles ? Things like distance can affect a relationship and personally I'm a believer that long distance relationships can only work if the couple is committed to each other prior to a seperation. Ask yourself these questions, and if you really have nothing to worry about then you really have nothing to lose by trusting him. If he breasks your trust then dump him, he's a loser, and you'll move on and be happier eventually.