Was Paul married?

Phil 4:3 reads:

And I intreat thee also, true yokefellow, help those women which laboured with me in the gospel, with Clement also, and with other my fellowlabourers, whose names are in the book of life.

The Greek term translated as “true yokefellow” is γνησιε συζυγε. There has been some debate throughout the centuries if this is a reference to Paul’s wife.

Another relevant pericope would be 1 Cor 7:7-8:

For I would that all men were even as I myself. But ever man hath his proper gift of God, one after this manner, and another after that. I say therefore to the unmarried and widows, It is good for them if they abide even as I.

While attempting to defend the apostolic origins of priestly celibacy, Jesuit scholar Christian Cochini in his The Apostolic Origins of Priestly Celibacy (Ignatius, 1990), admits that there are some early Christian authors who accepted that Paul was at one time married based on these verses. For instance, Cochini writes (p. 75):

 The word συζυγος (literally, yoke mate) is used at times in the Greek language to describe the wife; certain authors during the patristic times deducted from that Paul had been married.
 Clement of Alexandria († ca. 215) seems to have been the first to have adopted such an interpretation. He does not doubt that Paul had been married and sees a proof of it in Phil 4:3: “Will they [the Encratites] also reject the apostles? Indeed, Peter and Philip had children. Philip even gave his daughters [in marriage] to men. And Paul does not hesitate in an epistle to greet his woman companion, whom he did not take along with him for the good of the ministry” (Stromata, III, 6).
 Methodius of Olympia (cf. 240) sees in 1 Cor 7:7-8 a clear reference to Paul’s widowhood: “Here, too, he [Paul] stresses his preference for continence; he gave himself as a signal example to invite all his listeners to follow him in this state of life, by teaching them that it is better for one who had been married to an only wife then to remain alone, as he bound himself to do so.” (Le Banquet, XII, 82-83)

Was Paul married? We will never know for sure, but there are strong implicit evidences for Paul being married (and perhaps widowed prior to composing 1 Corinthians).