It depends on whether you have integrity or you are "stupid..." It is obvious she has no integrity, and cannot be trusted. If you want a relationship with that type, you are setting yourself up to be hurt -- physically, emotionally, legally, financially, etc. Obviously it is not smart to get involved with her. Choose a better option--rather than her--and you will be glad you did!
S.one I know had the same problem. you know what did he do?! he pretended that he has an other woman too! and when the woman who was flirting with him understood that she got very angry but as she knew she was in the same position she could not complaint at all! and at last... she left him forever!!!