No. Such content is vulgar and inappropriate for public sharing. It violates moral and ethical norms and may also be against the rules of many platforms.
No, it's not a common phrase at all. In normal English usage, it seems rather strange and not a typical expression you would hear in everyday conversation or see in general writing.
The phrase 'She loves me, she loves me not' is a quintessential part of the romantic fiction genre. It captures the essence of the emotional rollercoaster that characters in these stories often experience. Writers use this idea to build tension and anticipation, leading readers to keep turning the pages to find out whether the love is truly reciprocated or not.
We should firmly oppose it. If it's on a platform, report it so that the platform can take appropriate action to remove or restrict such inappropriate content.
She dates him perhaps due to some aspect of their sexual relationship or attraction. But this is a very general and more acceptable way compared to the original statement.