I agree with you that one of the main reasons for our lack of conflict is that we agree on the ground rules. We have a consonance of meanings and values. That is the bedrock of our relationship. These are not seen in agreement on the little things of habit and behavior, but rather in the underlying truths that motivate each of us. I could go further into what they are, but what they are is not the point; the point is that they are.
Once these values were seen to be aligned, our differences did not feel threatening or disturbing and we could relax and revel in the uniqueness of each other.