Overreacting? *long story*

Yesterday I got separated from my husband at a fair we went to. He was going to talk to a vendor about something and I was right behind him when a lady at another booth handed me a sample for some kind of eye cream and asked if I wanted a demonstration of the product. I thought it would only take a minute and my husband was less than five feet away. It happened so quickly I didn't have a chance to give him the heads up, but as he was involved with the person he was talking to, I thought it would be fine.

The demonstration took about three minutes and when I left the booth, my husband was nowhere in sight. I looked for him in the building, didn't see him, and then walked to the next building, where I found him with his dad, listening to a guy playing music. I leaned over and said hello and then slipped into a seat behind them, as I didn't want to crawl over people and make a spectacle of myself. I didn't think this was a big deal, but once the show was over and I tried to explain what happened, my husband just kept interrupting me with these skeptical, "mmhm" noises that made it very clear that he didn't believe a word I was saying.

After we dropped off his dad, he turned to me and accused me of "disowning him" because I had disappeared and then sat behind him at the show. He followed that up with a threat to jump on his bike tomorrow and just leave it all behind him. I told him the whole story, but he is determined that I deliberately slighted him and am in no way telling the truth. I disowned him and that's that.

Is he overreacting or is this justified? I don't know what to make of this. We had been having a really fun day before that happened.