This depends on what you want to do. Most men and women enjoy receiving oral more than giving. If he wants you to give him a BJ, then he needs to reciprocate and give you some too... and vice versa.
You say you've had sex with him about 3 times. Sex can mean a lot of different things. Are you referring to oral, "regular" vaginal penetration, or anal? If you've only done oral and that's what you enjoy.. just have fun with it and move on when it feels right. If it's the other way around, why don't you try starting with oral as part of foreplay... and you can enjoy it as much or as little as you want.
Talk with him and see how active he wants to be, tell him how active you want to be, and come to an understanding somewhere in the middle (if your desired amount differs).
Have fun and enjoy! :D
