I actually answered a very similar question not long ago focusing on the era of the first season of Outlander (but broadly true if the whole century). The tl;dr is that we have literally no idea of the prevalence of sexual assault in the past - heck, we have only an estimation for how prevalent it is today because it's still underreported - so the rapes portrayed in the show can't be said to be historically accurate or inaccurate. (And therefore anyone claiming that women were under constant threat of assault in any period is basing their opinion on what they feel is true rather than any kind of historical proof.) Most sexual assaults likely involved an acquaintance rather than a violent stranger (then as now) outside of wartime conditions, but to say that they all did would be ludicrous.