Love is the wish for others to be happy, and is based on understanding that everyone wants to be so. It can be extended equally to everyone, regardless of their relation with us or what they’ve done, and it expects nothing in return. In Buddhism, love is the greatest source of happiness.
Love versus Attachment
Love is often accompanied by other emotions. With unhealthy attachment, we exaggerate someone’s good qualities – either actual or imagined – and deny their shortcomings. We cling to them and get upset when they don’t pay attention to us, thinking, “I love you; don’t ever leave me; I can’t live without you.”
True love is the desire to maintain the happiness of all beings impartially, regardless of whether we like them or not. – Yongdzin Ling Rinpoche
Love in Buddhism has a feeling of closeness with others, but it isn’t based on whether they also love and care for us, and so there’s no dependence on anyone. Love mixed with attachment and dependency is unstable. If the person we love does something that hurts us, we might no longer love them. Just look at how many marriages start with love and end in divorce! When we’re free of expectations, nothing can sway us from it. Just as parents always love and want the best for their naughty child, developing stable love gives us the strength to deal with even the most challenging people. It takes training, but all of us have the ability (See How to Develop Love).
Universal love includes an often overlooked aspect: we need to love ourselves too. It’s not merely wishing for something to gratify our restless desire for pleasure and entertainment. The small amount of happiness we get from such things never lasts and we always end up wanting more.
If we love ourselves, we'll try to find true lasting happiness, not just temporary pleasure. It is when we really come to love ourselves, that we can truly love others.