If your relationship with this boy has been one of an exclusive nature up to this point then yes, I would tell him.

If you intend to spend time with this other person and you obviously know the nature of what you are getting into then doing it behind his back would not be right.

If you intend to have sex with her then he has the right to know if you are also having sex with him. He may not be interested in being part of your risky lifestyle.


Weigh carefully your circumstances. It may not be in your best interest to toss the boyfriend for a fling with another person. If you tend to be a selfish person, though, and by the nature of your post it seems that you are, you may just go ahead and have the fling behind his back anyway. Just remember, what goes around, comes around. Treat others the way you would like to be treated. It is a very simple and very positive way to conduct oneself.