Funny... I noticed my history file was open on my personal laptop today. I'm thinking my bf was checking my history file. I asked him. He denied it. He didn't see too convincing though. He has no reason not to trust me though... He knows before I was with him, I liked a guy in the army. He thinks we email each other. We don't. We used to.... but that was way before my bf, plus army dude is married now.
Anyway, trust is a big issue. You need to trust your boyfriend... if you don't it will ruin your relationship. I have many guy friends on my myspace, and my boyfriend knows it. He doesn't mind. You didn't say if they were just female friends... or questionable female friends (like on a romantic level).
I agree with Rosie if he is the littlest bit computer smart, he will know how to delete everything in his history.
On my computer the history is under a yellow star icon where you add your favorites. It give you the option of looking at your favorites, feeds, or history. It is so easy to delete it all though.