Do some women purposely hit on married men?

Yes because they have either been cheated on by their husbands or they are messed up in the head and dont want to see another woman happy because they are not or because of the challenge and the non committment on their part. Some men and women go after whoever they want, regardless of that person's relationship/marital status. Other people are invested in the challenge of "seducing" or "stealing" a person in a relationship. It can be an ego boost, they may believe it proves their desirability. As the previous poster said, some people may have been cheated on in the past and feel the right to revenge themselves by indulging in the same behavior, either with an ex or someone new. A person who repeatedly has relationships with married or committed people may use the partner's marriage as a barrier against emotional intimacy, staying with one person long term, etc. It may give them a feeling of security as a under the radar affair can never be a full, equal relationship.