She's not creeped out finding out Ellis' father is her former boyfriend and that she has been boning her former boyfriend's son? Yet, finding out about it she decides not to run away anymore. As if this is the perfect constellation to persuade her not to run away anymore.
What a screwed up family they're gonna be...
It might be a little weird for the Ellis and his dad.
Im sure that they will NEVER tell the mother. It will become an odd little family secret.
The son might have some questions about his dad, or how they compare. That he won't actually ask. And if he did, Adaline will not answer.
The dad might feel something along the lines, "LOL, i was there first and god damn, she looks as fine as I recall", and will keep it to himself.
I could imagine an odd scene or two, maybe at a pool party or something where the son catchs the dad checking out his wife/ex lover. Oops. Or worse, if he catches ADALINE checking out the old man! LOL.