Attention starved girl?

A girl that I work with is like my little sister. She’s married, very attractive and constantly being approached by guys that we work with and male clients. She says “I’m not doing anything to lead these guys on, I’m just being me”. Yet, she dresses seductively – mini skirts, skin tight clothes, , etc. – in a conservative business setting and the guys just go crazy for her. Females in the office roll their eyes at her, but she doesn't seem to notice or says they are jealous. She develops deep relationships with the guys that pursue her, constantly on instant messenger, email, text message, etc. with them and says they are her “friends”. About a year ago, she had an affair that ended badly. One of the other guys that was obsessed with her (not the one she had an affair with) found out about her affair. He started writing her anonymous notes calling her slut, tramp, etc. and threatening to tell her husband. Her manager at work saw one of the notes and had a talk with her because the notes were disturbing and he was concerned about her safety. The situation died down after a few months. She stopped briefly for a few months all the activity with other guy “friends”. Yet, now that threat is past and she’s right back to old ways. This is really hard to watch. I’ve talked to her about it numerous times but she just sticks to her story that she’s doing nothing wrong - can’t help it if guys stalk her or sticks to other story that they are just “friends”. Her husband is clueless as to what’s going on. What makes a girl like this tick? Is she just so starved for attention? I’m also thinking I need to drop the little sister relationship, distance myself and let the cards fall where they may.