Love is bigger than the part of it you can feel. Because it's so large, it gets mistaken for a piece of itself — usually the romantic sensation, which is among the strongest experiences available to a human being and is still only a fraction of the thing. The test Dave puts to it is a fair one: love is supposed to hold a relationship together. When the dishes need doing, the laundry needs folding and the rent comes due. Whatever gets you through that is the actual substance.
Practically, it's the other values in practice. You sense genuine love when someone brings grace and compassion to your imperfections and their own. When they have the courage to raise the honest thing, and the integrity to be the same person afterwards. When humility lets them admit they were wrong. When gratitude keeps them noticing your best qualities rather than cataloguing your worst. None of those are love in isolation. Practised together, in a relationship, they're what love actually consists of.
"Balanced" is the hardest word in the definition. Every value in this collection becomes something else when it's pushed too far. Compassion without honesty is enabling. Honesty without compassion is cruelty. Justice with no grace is punishment; grace with no justice is permission. Loyalty past its limit is complicity. Love isn't the maximum of these things — it's the balance point between all of them, held in a specific relationship, adjusted continually. Which is why nobody gets to do it well by accident.
It shows up mostly as attention. The research and the theology agree on this more than you'd expect. What people mean by "do you love me" is usually closer to "are you there" — and the answer is given hundreds of times a week, in three-second increments, long before anyone thinks to ask the question out loud.
That's what love is — not the feeling that begins it, but everything you practice afterwards.