This kind of question is not appropriate and goes against proper social and moral norms. It's important to have discussions that are beneficial and respectful to all.
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.
No, it's not appropriate at all. This kind of content is not suitable for public discussion or sharing. It goes against basic respect for others and the values of a healthy society.