If we don't know what we are giving, how can we attach a value to what we get back?

Basically, I sum up your post in that penultimate sentence.

Love is a deep bond and a decision to care for the other. We expect to receive support, respect and complicity, and in turn, to give the same with loyalty and commitment.

We value a relationship by trust, communication and the construction of a common project that makes us grow. We measure it by the well-being and peace it brings to our lives, in a healthy balance between giving and receiving.