"N.T. Wright's blunder on homosexuality," By Richard Fellows. 

Paul, I think, was against heterosexual sex outside of committed relationships (marriage), and it is safe to assume that he was also against homosexual sex outside of committed relationships. Paul's statements against homosexuality in Rom 1:18-2:4 and 1 Cor 6:9 do not state that gay marriage is an exception, but this silence is significant only if something similar to gay marriage occurred in Rome or Corinth in Paul's day. N.T. Wright believes that Paul was indeed aware of committed homosexual relationships: 

He gave the following comments in this video.

But one thing I do know, as an ancient historian, is that there is nothing in contemporary understanding and experience of homosexual condition and behavior that was unknown in the first century. The idea that in the first century it was all about masters having odd relationships with slaves or older men with younger men - yeah sure that happened, but read Plato's Symposium. They have permanent faithful stable male-male partnerships - lifelong stuff - Achilles and Patroclus in Homer - all sorts of things. 

Similarly, here, he writes: 

In particular, a point which is often missed, they knew a great deal about what people today would regard as longer-term, reasonably stable relations between two people of the same gender. This is not a modern invention, it's already there in Plato. 

In his Paul for Everyone: Romans Part 1, he writes: 

Nor is it the case, as is sometimes suggested, that in the ancient world homosexual relationships were normally either part of cult prostitution or a matter of older people exploiting younger ones, though both of these were quite common. Homosexual 'marriages' were not unknown, as is shown by the example of Nero himself. Plato offers an extended discussion of the serious and sustained love that can occur between one male and another. 

And he says, 

And as a first century historian I want to say the context in which the New Testament is written is one in which there was a lot of casual homosexual experimentation and whatever. But also as you see, hundreds of years before in Plato, people who were in long-term partnerships. So it isn't the case, as some have said, that the New Testament is simply opposed to a phenomenon which is quite different from what we know today. 

Have you spotted Wright's blunder? The problem here is that the evidence that Wright cites does not support his conclusion. Plato was a Greek writer, not a Roman, and his Symposium was written in 385BC. Paul refers to homosexuality only in 1 Corinthians and Romans, which were written to the most Roman of all his audiences, and he wrote more than four centuries after Plato. Homer's work, the Iliad, dates to the 8th century BC, so is even less relevant to first century Roman sexual practices, and there is no consensus on whether Achilles and Patroclus were homosexual lovers, and, according to Plato, their relationship was one of age dissonance.

As far as I can tell, there is little evidence for anything close to gay marriage in Paul's day. The evidence of committed homosexual relationships in classical Greece merely brings the lack of such evidence from the early Roman empire into sharper focus. Wright, who by his own admission is no specialist on homosexuality, seems to assume that sexual practices must have remained the same across the centuries. They did not. 

The example of Nero, cited by Wright, hardly provides evidence of committed homosexual relationships. Wright is referring to the 'marriages' of Nero to Sporus and to Doryphorus, as recorded by Suetonius: Nero XXVIII-XXIV. The passage, which doesn't make pleasant reading, is reproduced here:

XXVIII. Besides abusing freeborn boys and seducing married women, he debauched the vestal virgin Rubria. The freedwoman Acte he all but made his lawful wife, after bribing some ex-consuls to perjure themselves by swearing that she was of royal birth. He castrated the boy Sporus and actually tried to make a woman of him; and he married him with all the usual ceremonies, including a dowry and a bridal veil, took him to his house attended by a great throng, and treated him as his wife. And the witty jest that someone made is still current, that it would have been well for the world if Nero s father Domitius had had that kind of wife. This Sporus, decked out with the finery of the empresses and riding in a litter, he took with him to the assizes and marts of Greece, and later at Rome through the Street of the Images, fondly kissing him from time to time. That he even desired illicit relations with his own mother, and was kept from it by her enemies who feared that such a relationship might give the reckless and insolent woman too great influence, was notorious, especially after he added to his concubines a courtesan who was said to look very like Agripinina. Even before that, so they say, whenever he rode in a litter with his mother, he had incestuous relations with her, which were betrayed by the stains on his clothing. 

XXIX. He so prostituted his own chastity that after defiling almost every part of his body, he at last devised a kind of game, in which, covered with the skin of some wild animal, he was let loose from a cage and attacked the private parts of men and women, who were bound to stakes, and when he had sated his mad lust, was dispatched by his freed man Doryphorus; for he was even married to this man in the same way that he himself had married Sporus, going so far as to imitate the cries and lamentations of a maiden being deflowered. Clearly, Nero was not a homosexual in the sense that we would understand the term, and his "marriages" were not committed relationships in any sense. Suetonius's mentions of Nero's "marriages" to men appear in a discussion of Nero's bazaar sexual practices, and this suggests that Suetonius expected the idea of homosexual marriages to appear bazaar to his readers. Suetonius would not have written "he married him with all the usual ceremonies", if this was a recognized practice. Thus, Wright's mention of Nero's "marriages" backfires on him, doesn't it?

Wright says that there has been a lot of confusion about homosexuality, but I fear that he has added to it. Unfortunately many will turn to Wright and other famous writers for guidance on passages like Rom 1:18-2:4 and 1 Cor 6:9, but there is no substitute for consulting specialists and, preferably, the source documents.