You came out of work early then you remembered that your boyfriend has a band performance. You went to his performance to surprise him and you watched.

Everything was going fine, the play was great and you're enjoying it. Then when the play was about to end his girl best friend came to him and kissed him and instead of pushing his friend away he kissed her back and everyone yells and applaused.

He didn't noticed you and he continued to kiss his girl best friend in front of you and everyone.