I think that when you're in a relationship, it's easy to get in the habit of relying on your partner for your sense of worth. I think that that's a habit that damages both partners, and it isn't often readily obvious that any damage was done until the relationship ends and one or both people are left without a sense of worth.
This remind me of a passage from Jiddu Krishnamurti's Freedom from the Known:
You say you love your wife. In that love is involved sexual pleasure, the pleasure of having someone in the house to look after your children, to cook. You depend on her; she has given you her body, her emotions, her encouragement, a certain feeling of security and well-being. Then she turns away from you; she gets bored or goes off with someone else, and your whole emotional balance is destroyed, and this disturbance, which you don't like, is called jealousy. There is pain in it, anxiety, hate and violence. So what you are really saying is, 'As long as you belong to me I love you, but the moment you don't I begin to hate you. As long as I can rely on you to satisfy my demands, sexual and otherwise, I love you, but the moment you cease to supply what I want I don't like you.' So there is antagonism between you, there is separation, and when you feel separate from another there is no love. But if you can live with your wife without thought creating all these contradictory states, these endless quarrels in yourself, then perhaps - perhaps - you will know what love is. Then you are completely free and so is she, whereas if you depend on her for all your pleasure you are a slave to her. So when one loves there must be freedom, not only from the other person but from oneself.
This belonging to another, being psychologically nourished by another, depending on another - in all this there must always be anxiety, fear, jealousy, guilt, and so long as there is fear there is no love; a mind ridden with sorrow will never know what love is; sentimentality and emotionalism have nothing whatsoever to do with love. And so love is not to do with pleasure and desire.