Not sure if complicated psychological musing on self-loathing and learning to accept and love yourself or just smut...
Why not both?
She does seem to have severe lack of self-esteem. Perhaps, learning to love herself, even the parts she sees as flaws, will help her choose healthy relationships in the future.
So, instead of "selfcest" it's "self care."
Or, she's an incurable narcissist, and the only person good enough for her is her.