I am soon 18 and my girlfriend is soon to be 17, I worked hard on gaming her and eventually achieved my goal for traditional relationship with her but not before she fell in love with me deeply and I'd lie if I say I don't love her ( and no, this isn't because she fell in love with me, I've had that tons of times ) , she is sincerely what I've been searching for in a woman for a long time, PU just made getting to her more easily.

we are together for a little over 2 months now, but we dated 2 also so you could say around 4?
So yesterday we were together after a week we hadn't seen each other , making out talking etc' and then she says she wants to talk to me about my school prom that is in less then a month ( she cant come there from various reasons I wont throw SPAM )
she said : " for that one night only, I want you to feel completely free - forget about me for that one night, this is your last time with your school friends and I want you to feel released and be with someone if you wish "
I am a man of my principles and this is against everything I stand for, I love her and this is the reason i'm in a TRADITIONAL relationship with her - I told her that I dislike greatly what she said and she said that this is what she wants, and that inside it will bother her, but she thought about this decision a lot and this is the way she wants it to be.
so, what the hell? we are deeply in love - but she wants me to have a one night drunken stand with some slut i'll probably never see again?
is this a shit test to see if I will stand up to myself and show complete dedication to our relationship? is she afraid i'm gonna cheat on her there anyways ( if she does there aren't any previous implications that would make her think that, I never cheated on her and never seemed to be ) and that it will wreck our relationship, so she 'permissions' it and like that our relationship will be in the clear? , her prom is only in 2 years so I doubt shes expecting the same permission or is there another thing that slipped my mind?