Trying to seduce your husband has nothing to do with marriage - hers or your husband's. It's all about conquest and winning. If she is successful in getting your husband's attention off you and onto herself, then she wins a new trophy she can display for all the world to see, including her own husband.

Do not assume people have morals. Never assume that because someone is married that they are not also scumbags. This is a competition for her. She is obviously jealous of and threatened by you, and by your relationship with your husband. If she can cause problems between you two, then she feels powerful again.

Since she is a coworker, your husband could file a complaint with HR if her behavior continues. If she is creating a hostile work environment, the company will be required to either remove her from the area your husband works in, or if there are other complaints, remove her from the company completely.

It's nasty little girls like her that make success in the workplace still so difficult for so many women in the 21st Century.