I think I can understand where you are coming from - it's not just that you don't like her, but rather that your husband doesn't not like her like you do, and you wished he couldn't stand her - right?
But in all honesty, there is nothing you can do. He works there, so does she. She's his assistant, and there is a great deal of "brotherhood/sisterhood" that goes along with working with someone for eight hours a day, five days a week. They have to depend on one another - she as his assistant, and he as her boss. I know that I work with two men at my work - one under me, and one above me. We count on one another. Even though DF wouldn't want to, and probably doesn't like associating with them, he respects that they are my co-workers. I couldn't imagine him saying "I can't stand S and S." Why? He doesn't have to deal with them! And if he does, it's a pretty big sign that he is spending too much time at my work!!!
As long as she isn't mean to you, I see no reason why you should be bothered. If she is mean, talk to your DH.
But really, WHY is it that you can't stand her? You haven't really said.