I think it goes like this:
My mum told me I couldn't be loved. Long time ago, but I cling to this dogma, even though it hurts. Why? I must have some benefits from believing that. Oh yes, the benefit I have is:
If I don't let anyone love me I will never be smothered by someone.
Again, my mother. Very simple mechanism. I suffer because I can't be loved and I suffer when I'm loved.
Maybe it's not normal that when I imagine someone loving me I get a feeling of aversion? In fact, whenever there's a candidate for loving me that I don't want to lose, I rush into loving them first. Because then I don't get repulsed, I only get hurt. But I won't hurt them at least. And I'm "on top". I want to be the one who loves, rather than be loved, because then I have control. It's the "attack is the best defense" strategy.