I actually were somewhat close to utter the Q-word during last session as I had enough of being pounded for fun, but instead of quitting I decided that I will win this war, no matter the cost. And by winning I don't mean like getting 1 TP or 100 ducats, but something that will really hurt Porto.
So why would I want to hurt Porto?
Well, firstly, I got dowed twice by Porto last session, lost three very good provs to Sweden, not to mention that he only attacked my colonies in both wars and simply disregarded anything of my allies. So I feel that I'm being picked on during those wars.
Secondly, Porto let me down when we were allied, forcing me to cede most of my NA to England. "But Spain threatened" is so lousy excuse, because it wasn't like Breit would really have warred you.
Thirdly, I have noted that whenever one wins a war, there will be a rematch and one's enemy wants many times what you took in the first place. This always happens. Even Hive did so. So why the damn I should not do so?
If Seen wants to quit, he may. We will be needing new Porto and I doubt it's gonna be a fun position, because I will not lower my demands even if player changes. Any kind of lenitence is good only if you are many times stronger than your opponent or if you want to become friends with your current enemy. Otherwise it will just ruin your game.