How would you feel if you’ve been taking to/casually dating someone and they start flirting with someone else while drunk?

roxystars19
Friend of mine has been talking to this guy and she found out that while he was at a friends house, he began flirting with some girl. He was drunk at the time and the two of them (he and random girl) haven’t spoken since that night.
Technically, my friend and him aren’t dating, so he isn’t “cheating” on her. But I say otherwise.
How would you feel if you’ve been taking to/casually dating someone and they start flirting with someone else while drunk?
1 Opinion