When you throw a broken toaster out, you just go buy a new one and never think of the old one.
This is how the brain of people with serious mental illness feel.
It's not only you they discard, they do it to everyone.
What I've also learned is that they can and do feel love, but that feeling of love is scarier than any feeling in the world. They take good feelings as a threat, so they need to kill those feelings either with addictions, violence or just meeting someone knew.
They recycle people all the time.
It's not you, it's their lack of attachment to reality.