I'm just waiting for the joke to be that she's so happy after their wedding night sex that she loses her memories again.
It would be a joke in any case, but I once thought this might be a real possibility. We know that Arisa's original amnesia was triggered because she was so extremely happy (was it a marriage proposal?), so the spectre of a infinite-regress loop of [amnesia > recovery of memories > overwhelming happiness > amnesia] was certainly not out of the (wacky) question.
At this point I'm so invested in the happiness of these two darling uber-dorks that such an outcome now would be pretty horrifying. But the logic of the story's form of amnesia does imply the possibility.