Is it normal to not trust my girlfriend and her favorite guy friend?

I am sorry dude, but get a clue. He is trying to get her back and she is obviously still interested.
Go to the store buy a condemn and give it to her, tell her to have fun and see how she reacts. It is time for a new gf she has little feelings for you, that is obvious

You're a couple. Couples go to parties together. Show up anyway. Your friend is being disrespectful toward you. Chances are, he won't have the balls to throw you out after you've already shown up. Your girlfriend should have more respect for you than that too.

You have good reason to be suspisious. Find a friend thats a girl become really good friends with her go to her house etc and show her how it feels and if she has anything wrong with you being friends with her and going to her house etc you just tell her she has done the exact same so whats the problem. The fact you werent invited goes to show even if she doesnt have it in her mind he does.

It's really rude that you weren't invited- even insulting. If I were in her position I would definitely not even consider going without my boyfriend! Granted, it is a new relationship, but still, I think her going would show insensitivity to say the least. I would be very bothered about the whole thing as well. Your 'friend' sounds like he doesn't have much respect for your relationship.

Warning

Thanks that has to be the best advice. The thing I dont get is why miss me if she doesn't have to? The difference between the you situation and my gf and her friend is that her friend likes her and they even dated, although it was just two or three days. So idk, but I'll have a heart to heart with her about it after sex because I can talk some sense into her lol.

How long have they been best friend close for? All of my close male friends I've been close to for at least 5 years, if I strike up a new friendship with a guy we either don't become "best friends" or there's a romantic spark because things change with age.
I've noticed when I'm in a relationship and my other half is around with my friends I act a lot more reserved (maybe I don't want him to know how tapped I am) so sometimes it's nice to get away alone with my friends. If it were just the two of them I'd be suspicious but it's not.
It's so difficult having close male friends when you're in a relationship, so far you have no reason to doubt her, if you're insecure about it talk to her but don't keep going on at her about it because you have no idea how annoying it can be (I think I've been questioned about thia in every relationship I have been in).
This situation wouldn't really worry to be honest, she don't want you to talk to him as it will put a wedge between you both, she wants to be with her friends and of course she will miss you.
But that's just my opinion and I'm a bit of a spaz! Lol good luck

Yeah sounds way too fishy to me, u need to investigate this somehow. Whats disturbing is that she doesnt want u to say anything to him about the situation. u might consider having a serious one on one talk with her, watch her body language, look for inconsistencies in facts/events she may have told u about, etc etc. sorry, other than hacking into her computer to get passwords for emails/cell phone records so u can back track her activities/contacts, etc (which is what i would do personally), I dont know what to tell ya.

Is there some reason why she can't spend the break with you?