If you were in a serious relationship, would you mind if your significant other maintained an active profile on a dating website?

Needs context. 'Splain, Lucy. First and foremost, is she open about it or doing it behind my back? To me, it is more trust/honesty than sex or whatever. Second, what are our established boundaries -- not assumed boundaries, but verbalized and agreed upon boundaries. Which gets us back to #1. Third, why is she there? Forgot she was on it, has some contacts on it she would like to keep tabs on out of curiosity without carrying that relationship any farther, finds some of the posts a good laugh, etc.