Is it ok to flirt with a girl with a boyfriend that you know he is not worth it?

so there we were at a christmas party at a local bar when everyone just got pumped up for the mood of dancing when I saw particular pretty lady with some of her friends. so I made a move and invited her to dance with me, not knowing that she already has a boyfriend and he is actually inside the bar with her but quite distant but still she danced with me. so the night went on we were dancing, she started grinding and stuff but then it was going quite late and I one of my friend was already quite drunk so I have to get him home. so, I took a piece of paper and gave her my name and number.

the next day, I got a text message from her. we started communicating then after and realized that she has a boyfriend and told me that he is actually in the party we had. so now im quite indecisive whether im still going to communicate with her or not knowing that he has this apathetic boyfriend.