Pretty sure smurfy left lummy....and was completely fed up with him at the time that she did if I remember correctly (maybe I don't). She has a new life, new (younger) man, and new baby on the way, I really doubt any of this is about jealousy or resentment...jmo
I'd say party on if the kid in question were 20 or 21ish...but personally speaking I know the difference between 17 and 20 was gigantic as far as my ability to be mature in a relationship and make adult choices.