"Immoderate coitus" and sex at too young a age was seen as prejudicial to one's health at that time, and when Arthur died, and when the Infante Juan died (Catherine's brother) and King Louis of France (Mary Tudor's husband) and many others died it was said to be because of too much sex. At one point Henry VII advised Arthur not to cohabit with Catherine because of his health, if I recall correctly. Arthur was sick and of a weak constituition and perhaps the two were simply "put to bed" but didn't actually consummate the act, although it seems hard for me to believe they did NOTHING, ever; he was her husbadn, at very least he would have tried SOMETHING. I dunno. On the other hand I don't think Catherine would lie, her maids all backed up that she didn't have sex, plus the Papal dispensation provided for her marriage to Henry whether she consummated her union to Arthur or not.