Why would the Republicans want Anthony Weiner to resign?

I think all politicians who are caught with such scandal in their personal lives should be fired. We may go through a thousand politicians in every district, but you know, if they're putting that much of their time into their personal life, they certainly are not doing their job. That might scare the new ones into performing adequately and preventing their personal lives from overshadowing their professional lives. Not to mention, if they're lying to their own family, what hope do the rest of us have?