This song is not only about unconditional love, but about one-sided love or even domestic abuse. The speaker lets us know how she loves the other person even if they shame her, blame her and run around. Those are not the attributes one would describe love with. She does not speak of how well the other person treats her. The people outside the relationship may see how foolish the situation is, but the speaker does not want to see this. Telling us that no-one else really understands what happiness and love can be implies that she has built her own understanding or what love is, different from others definitions. It seems she is in denial, telling herself what she is experiencing is love, when in actuality her love is lonely love. She is unable to let go, because that would mean her love was not unconditional or real and she would have to face the cruel fact that she has been neglected.