Answer: This is natural because love evokes positive feelings in us and brings joy. As a rule, it does not cause pain and harm to anyone. A person is elevated through it.
It is not just about love between a man and woman. We are talking about love for children, for a neighbor, for nature, and for everything. Love is a positive feeling because it comes from the feeling of the correct attitude of the Creator toward the creatures.
However, in us, it clothes in our egoism and therefore turns into something opposite— into love for oneself and no more for anyone and anything else. It manifests itself on all levels: food, sex, family, wealth, power, fame, and knowledge.
Therefore, love dressed in egoism can be very cruel. It manifests itself in completely opposite qualities, in hatred for everything, the opposite to this love. However, this is just in our world.
And if we are talking about the upper state of love, there love is above our egoism, the same way it is in the external nature, like in the Creator.
From the Kabbalah Lesson in Russian 8/13/17