Is NOBODY wrong in the post ? POST : My gf and I were supposed to have a relaxing night I was cooking dinner, she spends the night and we watch our favorite shows.  I worked in the morning and afterwords I went home to clean my apartment before she came over.  Before I left a old friend who I haven't seen in a few months asks me to lunch having not eaten figured I might as well.
Well the gf knew when I left work and that I would clean the apartment but is upset that I didn't let her know I was going to lunch and that I took away time from us spending together.  To be fair if an old friend does ask me to out for a short time I will go because life's just too short. 
AITA? Cheers