Is Liza’s mother in any way responsible for the tragedy?

Is Erast a cold-hearted womanizer, who uses his gentry status to seduce naïve young girls. Or is he a sincere young man who is simply not strong enough to change his ways?

Can you think of any contemporary works (books, films, etc.) that utilize the theme of two lovers separated by their social standing?

Please be opinionated yet detailed.