I said it was "radically different" from my interpretation. I was using "radical" in the sense of "fundamental".

However, I believe that your interpretation is wrong. It certainly cannot be supported by what he wrote in De Bono Conjugali -- which translates to "On the Good of Marriage". Did you notice the word "good"? Someone as basically honest as Augustine would not call something "good" if he thought it was evil. He was certainly aware of Isaiah 5:20, "Woe to those who call evil good and good evil" and would not do such a thing.

He thought that procreation was the main "good" of marriage, but it was not the only good. He said that cultivation of the couple's relationship was a good, as it was a way of dealing with sexual desire, and so to avoid adultery.

Yes, he did say that sexual desire was evil in and of itself -- in De Genisi ad Litteram he comes close to saying that it would have been better if God had come up with some other way of perpetuating the human race (he does not actually say this, I believe from a reluctance to second guess God). However, let me repeat something from my original post:

Augustine suggests that procreation is necessary for the health of the human race, just as food is necessary for the health of the individual. "Neither activity is devoid of pleasure for the senses, and when this is regulated and put to its natural use under the restraint of moderation, it cannot be lust." In his review of his writings at the end of his career, the Retractions, Augustine provided an explanation: "I said this because the good and right use of 'lust' is not 'lust.' For just as it is evil to use good things in the wrong way, so it is good to use evil things in the right way." Although Augustine asserted that there was something "evil" about unrestrained sexual desire, he maintained that in respect to intercourse within marriage, the evil of lust ceased to be evil when it was directed to its proper purpose, procreation.

In other words, to say that Augustine saw sex only as something evil is to misread him.