Disagreements are underdiscussed issues (not enough discussed) and don't let to feel unity.
The real love is about the absence of disagreements. The logic is simple. If you can discuss everything, disagreements and tensions in relationships don't appear.
Every man has unique speaking style and every woman has unique type of listening. If they match, the couple has rich, profound, fruitful communication and interesting life. So, in such relations there are 3 times more discussions and man-woman interactions, than in ordinary family.
Igor