Filipino Expats Qatar

hi...i'm new here. and i know not if its d right place to post my querry....
can somebody help me where am i suppose to know if a person has already went out of Qatar?
There's someone i suspect has had a relationship more than that of being friend with my husband. She's the reason why I came here. But unfortunately, she's resigned from the office and nobody knows where she is now.
I'll be leaving Qatar sooner, and I fear she has intention of coming back. Can I have her banned from entering here?