Bishop must be husband of one wife.
St. Paul said that in his first letter to Timothy, chapter 3 verse 2.
Roman Catholic Church has three Western Rites and 22 Eastern rites. Bishops, priests and deacons are clerics. Latin, Ambrosian and Mozarabic are Western Rites. Celibacy is obligatory for priests in Latin, Ambrosian and Mozarabic rites. Celibacy is not obligatory for priests in most of the Eastern rites. Celibacy is obligatory for priests in Syro-Malabar and Syro-Malankara rites which are Eastern rites. Celibacy is obligatory for bishops in all rites.
Latin rite is spread all over the world and in these years many scandals regarding priests have come to light. Some scandals have involved bishops. One bishop is said to have fathered children from three women. Later he became the president of Peru. In USA many priests were involved in sexual abuse of boys and some dioceses had to pay huge sums in damages. The revelations about Fr. Macial Maciel, founder of Legion of Christ, shocked many. One of his defenders had to apologise. However a priest being found on a beach with a woman in bikini does not mean he has committed any sin, even if he is a radio talk host and has followers in USA and Latin America. It may be unexpected but not adultery or fornication or sin against the order of nature.
Clerical celibacy is of ecclesiastical law. In the first three centuries celibacy is not obligatory for priests in Latin rite. Synod of Elvira in 306 decreed clerical celibacy. It was not enforced till the Council of Trent in the 16th century.
Catholic Church does not impose celibacy on anyone. Priests accept celibacy willingly. Most of them remain faithful. Some fail. The failings make news. In recent years the scandals have been too many. In USA about 24 million people have left the Cathoic Church over the years.
Should those who have already become priests and bishops be allowed to marry? Considering the number of scandals it is better to allow them to marry. The number of priests has decreased in many countries over the years. With clerical celibacy remaining it may become even less. Considering the number of scandals in the Cathoic Church it seems desirable to allow clerics to marry. Then they will have families and there is need to think about meeting the expeses of their families. Transfers will create problems.
Protestant churches do not have obligation of clerical celibacy. They have less scandals. However divorce rate for pastors is said to be higher than ordinary Protestants. Besides, some pastors and bishops have engaged in homosexuality. Making clerical celibacy optional will not mean there will not be any scandal.
Benedict XVI will have to decide about making clerical celibacy optional. So far he is not in favour of it. However rising number of scandals makes it necessary to think about it. If he thinks these scandals will go away and church will emerge stronger he is free to continue with obligatory clerical celibacy.