This may not be the “best” relationship, but it is definitely the most realistic relationship in the entire manga. All of the other relationships are fairytales. You see all of the good things, but none of the bad things, and every relationship is going to have bad moments. It’s the goal of those in the relationship to fix it and move toward, or if worst comes to worst, to abandon it altogether.
It’s always nerve wracking whenever you get a chapter with these two, but it’s because it’s so nerve wracking that it makes it the most interesting.