I dont know why it gets to me so much!

So I dont know what it is about Justin, but I am so jealous/ protective over him.  I dont want him to be friends with any girls and I dont want any girl to look at him much less talk to him.  I have never been like this before, I dont know what has made me like this with him.  When I see a girl write on his wall or even become friends with him it irritates me so much.  I just am so scared a girl from his home town will take him away from me.  I mean they are from there, knows his friends, likes the stuff he likes, all that kind of stuff.  I really dont wanna lose him and I sound so much like a jerk for even saying anything to him about it.  I mean I want to be honest with him about my feelings, just like I want him to do with me.  Should I keep this to myself?  I really dont know, I want to be open with him but I dont wanna start anything about it.  I dont like girls...I really dont like them.  I know how they think, they watch until the guys post something bad about the relationship, like we you are arguing and then they message....thats when they pounce.  At first trying to sound concerned but then trying to slowly move in.  The guy just think she is being nice, but I see right through them. No this hasnt happened to me but I watch girls to make sure it doesnt.  Sorry ladies this guy is taken so back the hell off!!  Im not gonna put up with it!!