The wise man will not marry unless he turns aside from his purpose
Ok that seems to be the issue. You are translating it that way ("unless he turns aside from his purpose"), but the others are not, correct? Maybe this is an instance where there is some subtlety they properly detect and you do not? Do you have any other authority following your view? Do we know why they chose not to follow what appears to you to be the normal construction? Were they "correcting" the text?
I would agree with your view that the wise man would never turn aside from his purpose, other than perhaps in the sense of temporarily accepting some lesser pain for some greater pleasure later. But I do not consider that kind of decisionmaking to be really "turning aside from one's purpose" since the overall goal remains the same.
I feel like the sense that Bailey is conveying is most consistent with the philosophy and therefore most likely to be correct:
"Sexual intercourse, they say, has never done a man good, and he is lucky if it has not harmed him. Moreover, the wise man will marry and have children, as Epicurus says in the Problems and in the work On Nature. But he will marry according to the circumstances of his life."
In other words i would expect Epicurus to see some form of marriage and children to be most consistent in general with nature for most people (for the continuation of the species, as nature calls all species to survive). Therefore he would see it to be generally advisable, but would always allow the caveat that there may be individual circumstances personal to the person involved which would make marriage and children inadvisable or impossible.
I see the "marry according to the circumstances of his life" to be the caveat that goes almost without saying in regard to any activity of life. And I see the awkward wording as the result of D.L. describing and condensing the principle, rather than quoting Epicurus directly.
I would see Epicurus' general viewpoint best expressed by himself, in his will, when he provided for taking care that Metrodorus' daughter be married to a member of the school when she comes of age. To me that is the gold standard example of what he really thought, and the awkward wording is the fault of D.L. rather than Epicurus.
This following sentence seems to me to be inconceivable otherwise, as both a daughter or Metrodorus, and a member of the school, both of whom I would presume to be highly valued by Epicurus, and whom he wanted to be wise people, were involved:
"Let them likewise provide for the maintenance of Metrodorus's daughter so long as she is well-ordered and obedient to Hermarchus; and, when she comes of age, give her in marriage to a husband selected by Hermarchus from among the members of the School; and out of the revenues accruing to me let Amynomachus and Timocrates in consultation with Hermarchus give to them as much as they think proper for their maintenance year by year."
Now we could speculate that special circumstances were involved here, and that we have the unusual case that both spouses were presumably Epicurean and therefore knew how to handle "marriage" better than most people. Or perhaps the special circumstance was that they were part of the school and had a support structure around them, or money. But I doubt that Epicurus saw them to be an exception to the rule, since he generally seems to have thought that most people had the capacity to understand "right reason" and live according to his views. But I do think also that the point made by A_Gardner and others that we need to look carefully at what Epicurus considered to be the nature of marriage. Very possibly like justice itself he considered a marriage agreement to be like other agreements, that could change with circumstances, But that's speculation too - the only thing I think is beyond the reach of speculation is that Epicurus would not see a wise man turning aside from his purpose of seeking to live happily - I think it's inconceivable he would take that position about anyone who is wise.
