How do you handle the boring stretches?
Every long relationship goes through plateaus — periods that lack the early electricity, where the daily rhythm is functional but not particularly exciting, where neither person is at their most interesting because life is just being lived without ceremony. The couples who survive these stretches are not the ones with the most chemistry in the peaks. They're the ones who have something — a habit, a philosophy, a shared activity, a way of being together that doesn't require peaks to feel worth it. Ask what they do during a flat week. How do they handle a period when work is draining and there's no energy for anything interesting? What does a boring Saturday look like, and is it companionable or isolating? The answer tells you whether they have a strategy for the middle of the story, which is where most of life happens. Everyone can do the beginning. The question is whether they can do the long, unremarkable middle.