Is OTHER wrong in the post ? POST : Gf and I have been together for almost a year.  Before and during our dating she never mentioned being attracted to women.  

Last week she told me that she thought maybe she was bisexual and wanted to try out a threesome with another girl.  I’m not into the idea at all and told her I really wasn’t comfortable with it.  It turned into a fight.  She told me it’s every man’s fantasy and really didn’t get why I was uncomfortable.  It’s not my fantasy.  
 

Last night she brought it up again.  Now she wants to have a free pass.  Where she can have sex with a girl without me even being involved.   She said I could have a free pass too, but only with guys to “be fair”.  This is a bullshit free pass.  I’m not attracted to men at all.  I told her no and it got tense.  

I can understand her wanting to try and see if it’s for her, but it’s just not a fair situation to me.  She basically just wants to cheat on me and for it to be ok. It would be fair if my free pass was with a girl.  And as ugly as that situation feels I might agree to that.  