Personally, I don't have a problem with incest, be it due to legitimate love or just genuine curiosity at a young age, the former is just how love works and the latter is usually a passing phase.
What I do have a problem with is the mother, Jesus Christ, bringing up her children to have love from a young age is not something you should do, especially when they didn't know about it in the first place, she has practically ruined their entire teenage life because if one person in their school somehow manages to find out then that one person will make their entire school-life god damn miserable, and incest isn't exactly accepted by the majority of society.
Let your kids find out about love by themselves, don't force-feed them the knowledge from birth for forgets sake.
Ignore this post past the second line if the quote is fake, I only read up to the tenth page of this topic