Erich Fromm said this quote
“ Love is possible only if two persons communicate with each other from the center of their existence, hence if each one of them experiences himself from the center of his existence.Only in this central experience is human reality, only here is aliveness, only here is the basis for love. Love, experienced thus, is a constant challenge; it is not a resting place, but a moving, growing, working together; even whether there is harmony or conflict, joy or sadness, is secondary to the fundamental fact that two people experience themselves from the essence of their existence, that they are one with each other by being one with themselves, rather than by fleeing from themselves. There is only one proof for the presence of love: the depth of the relationship, and the aliveness and strength in each person concerned; this is the fruit by which love is recognized. ”