I'll post just a few comments on adultery (moicheia) and the mean, to reply provisionally to Lesley Brown and some points made by commentators.
In my view, V.2.1130a24-28 indicates that, for Aristotle, the wrongness of moicheia is potentially complex.
e)/ti ei) o(\ me\n tou= kerdai/nein e(/neka moixeu/ei kai\ proslamba/nwn, o(\ de\ prostiqei\j kai\ zhmiou/menoj di' e)piqumi/an, ou(=toj me\n a)ko/lastoj do/ceien a)\n ei)=nai ma=llon h)\ pleone/kthj, e)kei=noj d' a)/dikoj, a)ko/lastoj d' ou)/:
Again, suppose two men to commit adultery, one for profit, and gaining by the act, the other from desire, and having to pay, and so losing by it: then the latter would be deemed to be a profligate rather than a man who takes more than his due, while the former would be deemed unjust, but not profligate.For Aristotle, I think, adultery involves the commission of an injustice, which a person may or may not have been motivated to commit out of the vice of self-indulgence or akolasia. (See also his inclusion of moicheia in the list of injustices at V.2.1131a6.)
Lesley Brown's helpful remarks are a reminder of how Aristotle would likely have explained its injustice. Whereas I, at least, would want to say that adultery is the violation of a contract (or covenant), so that the primary wrong is always an injury to one's spouse, Aristotle--in accordance not simply with ancient Greek culture--would likely have held that adultery is a wrong only because it wrongs a man to whom some woman 'belongs'. For a man to commit adultery with another man's wife is not unlike robbing that man of his property; and, if the adulterer is married, the wrong would not consist in some offense against his own wife. Similarly, for a man to 'debauch' a free woman is for him to injure a man to whom she now 'belongs' (her father or brother) or to whom she will 'belong' (her future husband).
If the wrongness of adultery is primarily a matter of injustice (however we characterize the principal injustice), then whether it is violative of a mean reduces to the question of whether injustice is violative of a mean--which Aristotle asserts, although he is aware that the mean operates differently in the case of justice, as compared with other virtues of character.
But more on this tomorrow. And perhaps I'll share with you also a fascinating, true, and very clear example of 'adultery for the sake of monetary gain' which I came upon when collecting case studies in accounting ethics.