Why do some women flirt with every man they see?

I’ve encountered this female many times at her job and every time I see her, she’s always flirting with every and any man she sees. She’s come in with hickeys all over her neck and tried to hide them. She says she has a boyfriend, but yet she will openly flirt with every man that will be present. I’ve seen her openly flirting with her male co-worker.

Today one guy asked her in a joking (but semi-serious) way what she was selling, because every guy that was in and out of that place, she was flirting with or telling the guy to call her. Now I’m trying to assess for curiosity sake, what type of person does this when they supposedly have a boyfriend?

I say it’s low self-esteem, because if your ego is intact, I don’t think you need confirmation from everyone that you’re desirable. I flirt from time to time, but it’s always with someone that I’m genuinely attracted to and not just because I’m insecure like I feel she is. Comments?