My boyfriend is Friends with my ENEMY!!

I think you need to have a serious discussion with him.  Tell him that you know it may sound silly to get upset by something over the internet, but that this is today's world.  The internet and myspace/facebook are ways to express how you feel about someone, if they respect you, how they want their friends to think of him and you... etc.  Tell him that the way he is presenting himself on the internet is not OK with you... that you want an explanation and a change.  You also want to know why he is acting like this in front of others.  It makes you want to break up with him.  See how it goes.  Maybe you need to move on and find a more loyal and serious guy. 

this situation needs a confrontation. you need to ask him if he prefers you move on. nothing gets a guy thinking and talking when his relationship is in jeopardy. let him know how his web page makes you feel. after he is over being upset you may be surprised to find out that he did it to give you an idea of how he felt and did it to get back at you.. a real man will correct his web page if he tends to stay with you and work it out and also set the record straight for anyone who fed into the situation.

Listen to me.  Run as fast as you can.  He is a creep and so is she.  Why would you want friends like that.  Have more respect for yourself.  They sound like children. You can find a guy who is honest and loving and cares about you.  Please forget about those people.  Your life will only get worse.