AITA BREAKUP

My gf and I were supposed to hangout after a work dinner (nothing serious, the people there weren't her boss or anything) she had. Work dinner wound up going late and she asked me if we could go out with her work friends instead of hanging out just us. I agreed and walked 20 min to where they were. They take an extra 15 min to leave the restaurant. It's her and three male work friends and when I walk up none of them say hi or acknowledge me besides my gf so I don't say anything to them because I'm starting to get a little annoyed at this point (these guys are each at least 5 years older than me if that matters). We wind up walking another 30 minutes to a bar while I'm sweating my ass off because I did not plan on walking miles. On the walk, my gf talks solely to her one friend about work stuff and makes almost no effort to include me. By the time we get to the bar I'm pretty fed up and not very interactive but put in a reasonable effort to be personable. End of the night she's breaking up with me for my behavior. AITA?