My husband thinks I'm controlling after I asked him to limit contact with a female coworker

Assalamu alaikum, I really need some advice because I'm starting to doubt myself. I got married last year, alhamdulillah. Earlier this year, my husband attended a female coworker's wedding. I was fine with him going since they're just colleagues-she even came to our wedding-and he showed me photos and videos from it. No problem there. A month later, he asked me to list some items on eBay for him. We sell things together, so I needed pictures from his phone. While I was looking, I found a video from that wedding. In it, I saw my husband and this coworker dancing and holding hands. That really upset me because holding hands with a non-mahram woman crosses a clear boundary for me, and he knows this. When I talked to him, he said that since it was her wedding, he thought it would be okay, and she danced the same way with others. He also checked with other coworkers, and they saw no issue. After that, I told him I wasn't comfortable with him talking to her outside of work about non-work things. The video really hurt me, and I couldn't get it out of my mind. I knew they'd still talk about work, and that's fine. He agreed to this (though now he claims he doesn't remember agreeing) and even told her that I was unhappy because it was affecting our marriage until we cleared the air. Now, yesterday, he handed me his phone again to do some tasks on a work app while he slept. I finished and, as usual, closed all his open apps. I saw a preview of Snapchat and noticed he had messaged this coworker. I was confused because we had agreed he wouldn't contact her outside work, yet they had been replying to each other's stories, and in one message, he called her "Hun." When I confronted him, he said I'm being controlling and telling him what to do. I feel betrayed because he went against our agreement. He argues that he used to call people "hun" or "love" at previous jobs, so why is this different? I told him the difference is that he knows how I feel about this particular person. Am I overreacting? He says I'm making him go crazy because everyone he's talked to says he's done nothing wrong, and he believes the same. Just to be clear, I don't think he would cheat. I just feel so lost.