This is actually amazing.

The fact that they are actually having to pause and think about whether they should let their daughter go on thinking one of them is cheating behind the others' back rather than admit to her that they're a pair of degenerates means they intrinsically know there's something negative about their behavior that they either feel shame over, or don't want to encurage their daughter to replicate.

If there was nothing bad about their lifestyle, admitting it to the daughter would be a complete non-issue.

This is actually amazing.

The fact that they are actually having to pause and think about whether they should let their daughter go on thinking one of them is cheating behind the others' backs rather admit than admit to her that they're a pair of degenerates means they intrinsically know there's something negative about their behavior that they either feel shame over, or don't want to encurage their daughter to replicate.

If there was nothing bad about their lifestyle, admitting it to the daughter would be a complete non-issue.