The New Testament, unfortunately, never definitively states whether or not Paul was ever married. We are therefore left with looking for clues within his writings that might indicate whether, during at least part of his life, he had a wife.
What We Know
It is generally accepted that Paul, who was called Saul before his conversion, was not married during his ministry which ran from 33 to 68 A.D. His ministry ran from the time he was about 31 years old to when he was roughly 66. The apostle reveals, in the book of 1Corinthians written in 56 A.D., what his marital status was at the time.
For I wish that all men might be even as myself. But each one has his own gift from God; one is this way, and another is that way. Now I say to the unmarried and to the widows that it is good for them if they can remain even as I am . . . (1Corinthians 7:7 - 8, HBFV throughout).
1Corinthians 7:7 - 8 shows that the Apostle Paul identified himself with men who were unmarried at the time and with women whose husbands had died. He did not, however, identify himself with virgins or those who were never married (see 1Corinthians 7:25).
Paul later asserts that he and Barnabas, just like the other apostles, had the right not only to have a wife but also to take them on their evangelistic journeys.
Do we (Paul and Barnabas) not have a right to take with us a sister, a wife, as also the other apostles, and the brothers of the Lord, and Cephas (Peter)? (1Corinthians 9:5, see also verses 1 to 14).
Paul choose to not exercise these rights, meaning that he choose to be unmarried at the time, so as not to hinder the gospel (1Corinthians 9:12). Interestingly, even if the apostle decided to have a wife, the rigors of ancient travel and his hyperactive pursuit of spreading the gospel, along with infrequent financial support on top of being persecuted, would have made any marriage a severe challenge to maintain!
Factors to Consider
Some Bible commentaries state, with varying degrees of confidence, that Paul was never married.
"There is certainly nothing in Paul's known life which would lead us to suppose that the missionary apostle was ever married" (Popular Commentary on the New Testament).
There are, however, a few factors worth considering regarding whether or not Paul was ever married.
Sanhedrin Member
One of the intriguing questions about Paul's life was whether, before his conversion, he was a member of the Jewish Sanhedrin. The Sanhedrin, also known as "the council" (Matthew 26:59, Mark 14:55, 15:1), was the recognized religious authority over the Jewish people in the first century. It was composed of seventy-one members (the High Priest plus 70 others), many of whom were priests, who met in Jerusalem.
Membership in the Sanhedrin may have required a man to be married. The possibility of Paul being a member of this exclusive group is explored in our article dedicated to this topic.
Upbringing and Social Norms
The Pharisees were a very conservative Jewish sect that scrupulously observed God's laws and its interpretation by their predecessors known as the "traditions of the elders" (Matthew 15:1 - 2). Paul's father was a Pharisee who insured his son received religious training from Gamaliel, a highly-respected Pharisaic Rabbi (Acts 5:34, 22:3, 23:6).
Paul, after his religious schooling, became a Pharisee who, in his own words, surpassed many others in their zeal for Judaism.
And I was advancing in Judaism far beyond many of my contemporaries in my own nation, being more abundantly zealous for the traditions of my fathers (Galatians 1:14).
The Bible introduces us to Paul (Saul) when he was about thirty years old (Acts 7:58). Given the social norms at the time, as well as his family background, strict religious training and zealousness toward traditions, it seems incredibly unlikely Paul had never married before his conversion.
"It is not necessary to assume that Paul had never been married. Marriage was regarded as a duty among the Jews, so that a man was considered to have sinned if he had reached the age of twenty without marrying . . . A rabbinical precept declared that a Jew who has no wife is not a man" (Word Studies in the New Testament, commentary on 1Corinthians 7:7).
". . . twenty is regarded as a likely age for a (Jewish) man to be married . . . For a man, marriage was the only conceivable state; bachelorhood is never mentioned as a viable alternative." (Harper's Encyclopedia of Bible Life, section on marriage).
"Wedded life was regarded by the Rabbis as the most natural and the most exalted state. The unmarried man lives without joy, without blessing, and without good; also, according to others, without the Torah, without a wall (protection), and without peace . . . " (1906 Jewish Encyclopedia on Marriage).
Point of View
Paul's instructions on marriage in 1Corinthians 7 do not seem like they came from a lifelong bachelor with only a sterile and distant comprehension of this special relationship. His words betray his past experiences with this critical subject or, as stated in Halley's Bible Handbook, his words were written "by one who knew something of the intimacies of married life." (comments on 1Corinthians 7).
In conclusion, though the evidence is not conclusive, it seems highly likely Apostle Paul was married for an unknown period of time before his conversion. This would have made him a widower at the start of his ministry.