erastes

Okay, as a romance reader, to ME, once the protagonists of the book meet and commit to each other, THEN they must be faithful. If the hero has fucked every person he's met, it's a bit gross (Duke of Slut, anyone?), but even then, I can still believe that once he finds TWU WUV he won't stray as long as I believe in that TWU WUV. I think, for me, this comes down to how I think about marriage -- in real life -- it is a commitment to be with that person given in front of God and everyone, and you don't break that promise. You just don't. So if someone is breaking marriage vows, I get unhappy and think of that as unfaithfulness. (I know men can't get married to each other in historical romances, but I feel that a commitment is just as sacred for them, since that's all they can legally have.) I don't think of having more than one spouse (if one has died, or divorce has happened) or having had previous lovers as being unfaithful, either, as long as the having other lovers ends once a commitment is made.

(Edited to add a bit of clarity to my last statement)