I remember coming across a similar comment before reading WMF. However, afterwards I now think you are merely overlooking a very critical aspect of Kvothe's sex emergence....Felurian!

His urges were noted prior to his stay with her, so it was developing. He then spends upwards of a year (or many years) doing little more than fucking Felurian like mad and learning all there is to know about sex! This from a fae creature who is thousands of years old, and lives on sex!

So of course he emerges from that with a much different attitude and tool-set regarding sex. I don't think there's anything odd about it at all in that context.