Why Did I Cheat?

I broke up with my boyfriend two weeks ago after we decided it wasn't working out. We had been together for a year and a half, but the spark just wasn't there anymore. He's sweet and all, but we were in such different places in our lives, me wanting to get out into the world and him happy to settle down with kids right away. So I moved on, tried to find my footing again after being co-dependent for so long. But now, something weird happened at work last week that I can't stop thinking about. It started when this new customer came in; let's call her Mia. She’s a little older than me, probably in her late twenties, but there was just...chemistry between us from the first moment. We talked about everything under the sun, our jobs, our hopes for the future, even some funny and raunchy jokes. One day she came in looking particularly stressed out and I offered to make her a special coffee drink as my way of cheering her up. We started chatting more closely, and before we knew it, hands were brushing against each other while making change and flirting got bolder. And then, one day when the shop was busy, we ended up alone for a few minutes...and things escalated. It's not like I had any intention of sleeping with her that morning. But something happened between us; there was this undeniable attraction and she seemed so open to it. Next thing I knew, we were both pretty worked up and before either of us could stop ourselves, things went further than I ever thought possible during a workday. So here's the question: Was what I did wrong? Am I just trying to fill an emotional void with physical pleasure? Or was this purely about wanting someone new and exciting after my breakup? And am I really ready for another serious relationship so soon? Would love to hear your thoughts.