The information you provided is not detailed enough. I can't determine what type of novel you want to know. If you can provide more background information and plot details, I will try my best to provide you with useful answers.
No. 'Seduced by mom stories' are completely inappropriate. Family relationships should be based on love, respect and healthy boundaries, and such a concept violates all these basic principles.
No, it is completely unethical. Incestuous relationships go against moral and ethical norms in almost all societies. Such a situation involves a serious violation of family boundaries and the natural order of relationships.
One common element is the presence of something alluring. It could be a person, like in a story where a character is seduced by the charm of a new acquaintance. Another element is often a sense of mystery. For example, a place that holds secrets can seduce someone to explore it further.
A'seduced by mom story' could potentially be about a complex and inappropriate fictional scenario in some disturbing or unethical literature. However, this is a very abnormal and unwholesome concept that goes against normal family and ethical values.
I'm not sure what kind of romance novel you're looking for. However, according to your description, I can recommend a novel to you. The male protagonist of this novel was a prince. He fell in love with a hypocritical and vain woman who had once seduced the male protagonist's brother for wealth.
Sharing such a story that involves improper or unethical behavior is not appropriate. We should focus on positive, healthy and ethical relationship stories.
It's not very common. Straight guys typically have a heterosexual orientation which means they are attracted to the opposite sex. However, a well - crafted and engaging gay story might make them more empathetic or interested in the experiences of gay people, but not in a 'seduction' sense in terms of sexual orientation.