Do you think it's wrong for a married woman to have a crush on someone, like a coworker?

I think it depends on the nature of the crush and the nature of relationship for the married couple. I don't think there is anything wrong with finding someone attractive, that's not even something someone has control over. If the nature of the crush evolves to behavior that one is uncomfortable being open with their significant other about, that would be problematic to me. What that line is depends on the married couple. Some couples are perfectly content with their significant other sleeping with other people even though to most that would be completely unacceptable. I think most couples would be comfortable with their significant other having lunch with a co-worker. But, if you have lunch with a co-worker and feel guilty about it, I would question what you're getting out of your relationship with that coworker, are they just a friend or are they providing you emotionally with something that your spouse should be providing? If you feel guilty about the nature of your interactions with someone, I'd continued thatwrong and would suggest to do some introspection about why that is and if there is something within the marriage they might be lacking and needs to be addressed.