It's bad enough to be 'the other woman'. The man you love, torn between 2 women, doesn't belong to you- you come later, come after, crushed and pained by the awful awareness that he prioritises someone else over you and is unlikely to leave her for you. It's worse, and unbearable, to be 'almost-the-other-woman', that is, when you have unrequited feelings for a man who isn't single- married or in a relationship. Because in the former case, at least you're consoled by the fact that he has something for you, be it love or lust. Because you now stand in a distance, immersed in your own longing and sadness. Because you can't stop picturing in mind him and someone else, and wondering what he has said to her about you, to maintain her trust, to affirm his love and fidelity, to reduce her jealousy, to convince her that she's everything and you're nothing.
That she's everything and you're