Ahhh .. I knew someone would post that verse, and it turned out to be you! So what is Paul actually saying? Paul instructs that bishops must be married only once. This verse refers to bishops that were widowers. Paul is instructing that these widowers could not remarry. The verse also refers to those bishops who were currently married. They also could not remarry (in the Catholic Church's Eastern rite, priests are allowed to be married; celibacy is only a disciplinary rule for the clergy of the Roman rite). Therefore, this text has nothing to do with imposing a marriage requirement on becoming a bishop.
Paul was writting to the believers in Corynth, who were used to having more than one wife. He meant exactly what he said, a deacon, bishop... must be married to ONLY ONE wife!