Please, do, understand your girls for their sensitivity and insecurity. No matter how self-conceited they are, they've never asked for anything impossible. Your comforting words and effort of lifting them during those moments will be enough. Don't get mad or pissed off if they sometimes feel ugly or less valued, it only means that they are waiting for sweet words like "you are beautiful." Just be sure that you mean it. If their immaturity is getting on your nerves, then saying "it isn't about you," will never make us feel secure or more loved. I, myself, don't even think it's the best basis for everything. You're just hurting her more with your words.
"Insecurity" on some women can sometimes be serious for them, especially if it was brought on their early years, calling it childish or stupid will only hurt them more. And just so you know, it is an "unwanted" feeling/thought.
If you think everything about this is pointless, then just leave her.
Sincerely,
H
.
