Read more about Love from the works of the Mother and Sri Aurobindo.
What is Love?
Love is one of the great universal forces; it exists by itself and its movement is free and independent of the objects in which and through which it manifests. Love is only your capacity to receive and manifest this universal force. 
Love is in its nature the desire to give oneself to others and to receive others in exchange; it is a commerce between being and being. In its life-origin, the law of love is the impulse to realise and fulfil oneself in others and by others, to be enriched by enriching, to possess and be possessed because without being possessed one does not possess oneself utterly. 
What is Divine Love?
A supreme divine Love is a creative Power and, even though it can exist in itself silent and unchangeable, yet rejoices in external form and expression and is not condemned to be a speechless and bodiless godhead. It has even been said that creation itself was an act of love or at least the building up of a field in which Divine Love could devise its symbols and fulfil itself in act of mutuality and self-giving, and, if not the initial nature of creation, this may well be its ultimate object and motive. 
The Divine Love, unlike the human, is deep and vast and silent. 
What is Psychic Love?
Psychic love is a form taken by divine love in the human being according to the needs and possibilities of the human consciousness. 
Psychic love can have a warmth and a flame as intense and more intense than the vital, only it is a pure fire, not dependent on the satisfaction of ego-desire or on the eating up of the fuel it embraces. If love is psychic in its nature, it always brings a sense of oneness or at least of an inner intimate closeness of being. The Divine Love is based upon oneness and the psychic derives from the Divine Love. 
What is Human Love?
In human beings the first contact of love brings down something of its purer substance; they become capable for a moment of forgetting themselves, for a moment its divine touch awakens and magnifies all that is fine and beautiful. But afterwards there comes to the surface the human nature, full of its impure demands, asking for something in exchange, bartering what it gives, clamouring for its own inferior satisfactions, distorting and soiling what was divine.  f>
Love & Sex
All movements are in the mass movements of Nature's cosmic forces—they are movements of universal Nature. Sex, for instance, is a movement of general Nature seeking for its play and it uses this or that one.
It is not that it is not possible to keep the love pure, but the two things love and sex-desire are so near each other and have been so much twined together in the animal beginnings of the race that it is not easy to keep them altogether separate.In the pure psychic love there is no trace of the sex-desire, but usually the vital affection gets very strongly associated with the psychic which is then mixed though still not sexual; but the vital affection and the vital physical sex-emotion are entirely close to each other, so that at any moment or in any given case one may awake the other. 
Why is Love Essential?
As the love of the Divine grows that the other things cease to trouble the mind.
If the spirit of divine love can enter, the hardness of the way diminishes, the tension is lightened, there is a sweetness and joy even in the core of difficulty and struggle. The indispensable surrender of all our will and works and activities to the Supreme is indeed only perfect and perfectly effective when it is a surrender of love. 
The oneness which is self-existent and self-content is expressed as love, it is something wide and universal, untroubled and firm even when it is intense. This is in the basic cosmic oneness. 
How to Love?
One moves gradually in the gradations of love. Firstly, it takes the form of, If you love me, I shall love you". Then, there is a feeling which is slightly better than the former, If you don't love me, I shall love you." One should love because one cannot do otherwise but love. One loves for the joy of loving. There should be no bargaining in the mind and feelings. 
One will realise one day that love is not something personal, that love is a universal divine feeling which manifests through you more or less finely, but which in its essence is something divine. The first step is to stop being selfish. For everyone it is the same thing, not only for those who want to do yoga but also in ordinary life: if one wants to know how to love, one must not love oneself first and above all selfishly; one must give oneself to the object of love without exacting anything in return. This discipline is elementary in order to surmount oneself and lead a life which is not altogether gross. 
How to Love the Divine?
By becoming divine in nature [one can love divinely]. 
To become conscious of the Divine Love one must will it. To will it is a constant, sustained, concentrated aspiration, an almost exclusive occupation of the consciousness. This is the first step. There are many others: a very attentive observation, a very persistent analysis, a very keen discernment of what is pure in the movement and what is not.
By a Psychic Opening
The psychic element is the need of the inmost being for self-giving, love, adoration, union which can only be fully satisfied by the Divine. The spiritual element is the need of the being for contact, merging, union with its own highest and whole self and source of being and consciousness and bliss, the Divine. The mind, vital, physical can be the supports and recipients of this love, but they can be fully that only when they become remoulded into harmony with the psychic and spiritual elements of the being and no longer bring in the lower insistences of the ego. 
By Getting Rid of Lower Movements
If you are impure and egoistic, love in you will become impure and egoistic, narrow, sectarian, limited, ambitious and possessive, violent, jealous, vulgar, brutal and cruel. Is this the kind of love that can be offered to God? Refusing all mental agitation when it comes, also all vital desires and turmoils, and to keep the mind and heart turned as constantly as possible towards the Divine. 
How Does Divine Love Manifest?
The manifestation of the love of the Divine in the world was the great holocaust, the supreme self-giving. The Perfect Consciousness accepted to be merged and absorbed into the unconsciousness of matter, so that consciousness might be awakened in the depths of its obscurity and little by little a Divine Power might rise in it and make the whole of this manifested universe a highest expression of the Divine Consciousness and the Divine love. This was the supreme love, to accept the loss of the perfect condition of supreme divinity, its absolute consciousness, its infinite knowledge, to unite with unconsciousness, to dwell in the world with ignorance and darkness. 
On the physical plane the Divine expresses himself through beauty, on the mental plane through knowledge, on the vital plane through power and on the psychic plane through love. 
Read more about Love from the works of the Mother and Sri Aurobindo.