feeling guilty

hey everyone, i'm an artist and i just wanna get this off my chest. i've been engaged to my partner for a year now but last night we went out with some friends and i couldn't help flirting with another guy at the bar. it was all playful, we didn't do anything, but afterwards i felt so bad. like i betrayed my fiancé without even wanting to. we both know there's no real attraction there, but still... why did i let myself go that far? i keep replaying it in my head and wondering if he'll ever find out or how could i have been so stupid. anyone dealt with this before? what do you think?