ooh.
She's your girlfriend of 2 years but you tell her if she wants attention to go somewhere else?? If I was her, that would make me feel REALLY bad!! Not that you needed to take her to the party, but just tell her maybe that you wanna go out w/ the guys or something. And that you will spend some time with her at another time. Especially after 2 years. If I was w/ someone for 2 years and they told me that, I would be very upset.
She probably wouldn't have a problem w/ you going out w/out her, it might just be in the way you approach it. That is just coming from a womans point of view.
It's not that she doesnt trust you., but I would just be alittle more sensitive to her feelings.
Maybe she is saying she wants more attention from you because she's feeling like she feels like she hasn't really gotten any lately???
I'm not dogging you out AT ALL!!!!!! There is NOTHING WRONG w/ you wanting to get out w/ out her. But the way you approach it can make ALL the difference!!!!! .

Really.. just let her know that you enjoy your time together, but you want a little time w/ the guys....see if that doesn't make a difference!!!!!
Good luck to you and I hope ya'll work it out! Hope you dont mind my female p.o.v. and I hope it helps you some !

After I read your post, I had to tell you what I was thinking from a females point of view... I cant speak for the guys..,.I do hope its helpful to you to understand.... Hope yu work it out!!!!