Didn't know this was high school

Met a guy at a party while very drunk found out he was in a band and has a show the next day. He talk to me about it in the morning via text when I'm sober and I love concerts so I went to my hunger afterwords and I had a popping up having some really great sucks but that's a different story. At the concert since it was a small local thing he's actually up and tried to start shit and drama and I talk to some of his friends and they assured me she is an ex. Neither of us wanted anything serious and we like hanging out with each other so we decided to keep talking. The other day I went to a Nother party where his band was playing and before it even starts that girl comes up to me and asks my name I didn't recognize her so I play it we introduced myself like I would with anyone else.  She then tells me "that's my boyfriend so could you please just hop off his dick you've been texting him and just stop". Honestly if I wasn't so surprised oh damn I would've loved to verbally repair the shreds for that. And yes he was single when we hooked up. Earlier in the day I text him asking about a certain part of town because I'm still unfamiliar with the area and I'm looking for a new place to live and wanted to know like hey this is sketchy place to live or what. Nothing sexual completely innocent same thing I said to him I copied and paste it to at least three other friends who've lived here for years. When I got home I also checked all my social media and found that I've been blocked from all of his shit.