Two sex queries

So...I have two questions related to my post yesterday:

First, just after I saw Orgasm, Inc., I heard on the car radio an ad for some sort of herbal supplement for men (I wish I'd written down the name). The product was alleged to mimic or promote testosterone or something. The commercial acknowledged that the "condition" it supposedly treated was merely normal changes associated with aging, but focused - in addition to boosting vigor generally - on maintaining or increasing sexual desire.

I recalled at least one Roman writer* reflecting upon declining sexual desire with age and calling it a positive and enjoyable experience: men (I think they were writing specifically about men) are less likely to behave stupidly, and the weakening of those overwhelming physical drives frees them to focus on other aspects of their lives, especially their work. Now, I can see a specific situation in which a man's partner has a problem with his lack of interest in sex (not that this silly supplement would do anything for that beyond, potentially, the placebo effect). But I see the Roman writers' point, and don't really understand why people would want to artificially create desires in themselves, even if these can be satisfied. Why are some men interested in doing this?

Second, both PZ and Dan Savage have written recently about the mystery of the female orgasm, both leaning toward the "by-product theory" which sees the female orgasm as an evolutionary by-product of the male orgasm. This makes sense, but I've been confused about why the female orgasm is seemingly assumed to have no adaptive function because it's not needed for ejaculation. I could well be missing something important here, but I would think that the pleasure of orgasm, like other sexual pleasure, would incline women to have more sex. Is the assumption that female sexual interest/desire has played no evolutionary role whatsoever? If so, that assumption doesn't seem defensible in light of primate and human anthropological research.

With regard to the specific case Savage is commenting on, I think his advice to relax about it is good. We know that this can be strongly affected by psychological states, and being wound up about it can't be helping, even if it's not hurting. At the same time, cultural beliefs (and the feelings of shame that stem from them) and ignorance about sex (on both partners' parts) shouldn't be dismissed as possible factors because of an evolutionary hypothesis.

*(if anyone can remind me which specifically, please do)