This is my main problem as well...I'm still unsure as to what exactly the big deal with Dorian's quest is supposed to be....again, the game itself notes that there's nothing wrong with being a sidepiece (ee Vivienne and Leliana) so what exactly was Dorian's excuse?
Perhaps being a sidepiece is actually bullshit for some people, though. Sure, for an icy super-pragmatist like Vivienne, who's willing to forgive any "defects" for power and station, and revels in the Orlesians' ridiculous Game and will play pretend until she dies, perhaps that sort of thing might be grand (putting aside for a moment that she has no other option, being a mage in Orlais), but Dorian doesn't strike me as the type to give a snoufleur's bubble butt about that.
again, this assumes that heterosexual people can not feel revulsion to a person...and it still doesn't excuse his selfishness since his not having a heir means the end of the House. Really, I don't see how people can defend this since the game males clear that other than having a child, there's no reason why Dorian has to actually sleep with the woman more than once.
From what I've gathered in his banter, this also comes with the prospect of living out a life of marriage with someone he doesn't want, presumably until one or both of them kick the bucket. I guess he didn't have someone like the Warden to pull his arm into hitching up in that arrangement like what happened to Alistair. I can only assume that his basic response was "F*ck 'em", which I can dig.
Anyway, back to Calpernia. This lady's pretty much the single reason why I'm truly torn over the Templar path. People talked up Barris, but I don't really care about that guy. This character's more interesting than Samson overall.