4. We are told the love potion has ‘worn off’ after three years. Describe the reactions Tristan and Yseult have regarding this fact. Why is this the case?

After the potion wears off, Tristan, who is hunting at the time, "instantly [begins] to repent." This repentance is full of complaining for his own "suffering," his lost material goods, his lost status at court, his poor relations with his uncle the king. Eventually he is done complaining about his own sorry state and turns his thoughts to how his actions have negatively impacted Yseut: "She is in the wood, and she could be living withe her servants in fine rooms hung with silken cloths." He resolves to reunite Yseut with Mark.

Meanwhile, Yseut goes through a similar mental process, bemoaning her own fate and blaming Brangain for giving them the potion. Eventually Tristan and Yseut explain their feelings to each other and decide to return to King Mark as knight and queen, respectively.

I think that Tristan and Yseut react the way they do - quite selfishly, initially - because no matter how angelically Beroul tries to paint them, they are still human - and humans always look out for themselves first. Then, after they complain about the holes they are in for a while, their noble natures return to them and they present the other person's misfortunes as a reason to do something about the issue. However, I don't believe that either of them wants to reconcile with King Mark for purely selfless reasons. After coming out from under the potion's thumb, the first elements life that they regret missing out on are material goods (silks, furs) and societal conventions (servants, ladies in waiting). This leads me to believe that they are not quite the perfect, flawless models that Beroul wants us to believe that they are.