How do you tell your boyfriend you like another guy but you still want to date him?

You don't. If you like someone else there is a bigger problem here then. When you start finding your getting wondering eye, that usually means something is lacking in the relationship. If you feel enough for this person don't let it linger and exit the relationship. In all fairness to your boyfriend you don't need to hurt him more by telling him how you feel about someone else. Look at it like this, would you want someone to tell you?