I feel you. I came into SD17's life at 15 - prime mood-swing-teen-angst time. She would mouth off a ton, hole up her room, is now obsessed with hair and makeup and clothes, has no real hobbies or friends. When the kid is snotty - people tell you "OH shes JUST a TEENAGER, she'll get over it".

I don't think so. Psychologists say your personality is pretty much set by 12

When the kid is lazy, and does nothing to help, you hear "oh, that's ALL teens, EVERYWHERE, suck it up and deal with it!" I am thinking to myself, oh sure, deal with it and drive myself insane???? So she can move on and have a good life?

My situation is similar in that BM is "off" and does some crazy sh!t. BM, she drinks, gets crazy and mean. And takes medications. So the child has learned how to be crazy, lazy, unappreciative, mean, rude and a victim of her "ailments".

All you can really do is this: firstly disengage, and do your best not to get bothered. Take care of your children - be the best version of yourself. Because that little kiddling is watching your every move and hearing everything you say (to twist it sure), and is LEARNING how to be a woman from you too... next to her mother you are the most important and influential woman in her life. But disengage - you have no authority. Its a fine line to walk, and a very hard one.

Wow triplet toddlers! You've got your hands full, mama.
I agree with the advice to disengage, if you can. And, sounds your husband is copping out by saying he can't do anything about her. My husband says that when he doesn't have the energy to try harder with my SD. He'll say, "she's babied at her mom's house. She's spoiled at her mom's house. There's nothing I can do about it." And then when he does, magical things happen, like her saying "thank you" and cleaning up after herself, and participating normally in family activities...
Sounds like DH might just be exhausted. What a full house- quite possibly, you have 4 kids at home at the hardest ages, right?
She sounds dreadful. Maybe you can busy yourself with your little monkeys and manage to ignore most of what she says?
Not that I know, I don't live with a teenage yet.
May the force be with you.

normal teen behavior unfortunately..

Honestly, you seem to have backed yourself into a corner. No, it's not the case that a person is fully formed by any age. But when you look at your SD, you see a fixed personality, that you don't like, that you believe will never ever change. So I don't see how you could even hope for things to be different.

OTOH, all of those moments you didn't like could have been addressed, and values could have been imparted, critical thinking skills could have been laddered.

Big boobs scene, take 2:

December: Hi SD, I see your bra size has changed since I saw you last.
SD: ~~
December: What do you think the big fuss is about big boobs?
SD: (conversation about sexuality, women's role in society, SD's view of herself and others, the objectification of women, the importance of self-love and self-acceptance, ways in which SD appreciates her changing body, ways in which she's uncomfortable, etc etc)

OP, I think I understand where you're coming from about your SD and the feeling that you and DH cannot influence her. We are in a similar boat with skids. BM is a classic case of narcissistic personality disorder. Extremely materialistic, convinced she's perfect and everyone else isn't, only really cares about herself. She's a real peach.

Skids are 7 and 12. Current timeshare is 37%/63% with DH as NCP, and most of that time is at holidays and during summer. We have them Th-Monday AM every other week, as well. We really struggle with them because they're not being taught the values that DH and I would prefer and think are necessary for life. Neither of them is encouraged or allowed to exercise *any* independence when they're with their mother. Literally, SD12 still goes to the same sitter she had as an infant each morning before school. SS7 is not taught anything about kindness or gratitude, and BM is a classic helicopter parent with him, trying to move the world to accommodate him, instead of the other way around, making him next to impossible to be around.

DH is mortified by skids (particularly SS). He wants to teach them his values (DH is literally the kindest, most generous man I've met!), but feels like he can't in the time they're with us. He is reconciled to having and enforcing rules while the skids are in our house and to setting an example for them through our own actions. He can't fix his kids, but he'll do what is necessary to make it work when they're with us.

Personally, in the situation you've described, I would clamp down. She would wear appropriate (per me/DH) clothing during visits, and disrespectful behavior would be corrected consistently.

So, is it possible the stress of raising triplet toddlers is negatively affecting your perception of how "horrible" your SD really is? Because honestly I don't see wanting hair done up and mascara on before leaving the house as all that terrible. I'm not that way - I'm a farm girl at heart and I rarely wear makeup and do my hair. But my cousin and SIL are both the type that must be made up and dressed just right in order to leave the house. My mother was raised to never leave the house without make-up on. The push-up bra thing is irritating - one of my biggest pet peeves is the sexualization of children and how we make our kids grow up too fast in some areas and stunt them in areas like responsibility. But it's also something easily solved by "Not at our house. Our values are xxx and in this house that means you dress for your age."

The fact that your DH has "given up" because he realizes "he can't fix her and just shrugs it off" is the biggest problem you are having with your SD. She won't respect you or your values if your DH isn't consistently reinforcing his values. Your best option is to disengage. I'll admit I'm terrible at it, so the best advice I can give is to just take deep breaths and refer everything for SD to your DH. 'Ask your Dad' needs to become a mainstay in your vocabulary. I understand your frustration but it will help you immensely if you let go of the anger and dislike you carry for your SD. It will poison your whole life, and you really don't want to let anger with SD affect your life with your triplets.

My SD11 has a truly TERRIBLE victim mentality. Nothing is her fault. DH says it's exactly like BM. He hates it and privately we don't think we can really fix it despite trying to instill a sense of personal responsibility her entire life. But in front of SD11 he is on her every single time she tries to blame someone else. Every single time. DH may not be able to "fix her" but he damn well loves her enough to try his hardest, even when it means hearing her say 'I hate you! I want to live with Mom! You're mean!'

I have BS4 and BS1.5 (and SS10) and I know I'm less tolerant of normal kid behavior right now because having those younger two home when I need to work is driving me insane. BS4 is going through an incredibly whiny phase, and BS1.5 is resisting talking and throwing tantrums when we refuse to answer to gestures instead of the words he knows.

dup. sorry.