A Night of Betrayal

I'm engaged to someone I care about deeply. We're both in our twenties. Lately, my job as a bartender has been the only outlet for my stress and loneliness. Last night, a customer who had been buying rounds all evening seemed to notice me more than usual. He was quite charming, more so after some drinks, and we ended up talking intimately about ourselves. There were no secrets between us in that moment. Soon enough, he invited me back to his place. We went upstairs and... it happened. It's not something I'm proud of, but the intensity of that night is hard to forget. I've never felt this way before. The guilt is overwhelming now.