<human>: Could you distill the essence of the text into 1-3 sentences?

Sorry in advance because on mobile. My boyfriend [M26] of 1 year and I [F22] went to a music festival together recently. It was also our anniversary (this is important later). 

The day before our anniversary there was an artist performing who I really wanted to see with my BF, it's the only set I specifically asked him to go to with me. Instead, when I left for 10 minutes about an hour before the set to go to the bathroom and explore the venue for literally 10 minutes he wasn't there when I got back. Turns out he met up with some friends (who hate me and are rude at best to me) including one of whom he slept with while we were first dating (slept in the same bed with, although he swears they didn't do anything). He didn't want to meet up until after the set I'd asked him to see with me had ended (I asked him to see it with me 6 months ago when the lineup came out and he agreed). 

Am I right to be angry and hurt about this? Literally he could have met up with them at any other time and I wouldn't have cared (though it's still mad disrespectful that he lets them treat me the way they do and doesn't say anything or do anything about it)- but the day before our anniversary during literally the one set I asked him to see with me?
<bot>: BF and I went to a music festival, he ditched me during the one set I asked him to see with me. Do I have a right to be mad?