Hello all, I'm new to this so please bear with me. And when I say new I mean new to posting anything online ever. But like many of you I am at a loss right now. I'll obviously try anything and/or look for guidance anywhere. My wife and I have been married 7 years. We have 2 paternal twin 13 year old girls, my step-daughters. We also have a 5 year old and a 4 year old, both daughters as well. The eldest, by 2 minutes (a fact she repeats often), is tearing my family apart. She is a bully at school to her twin sister. She is mean and nasty to her two younger sisters. And every attempt I make toward getting my wife involvedj in addressing it, it drives a wedge between us. My wife thinks I'm too strict and says I see issues in things that aren't actually issues due the specifics of my own upbringing. I don't feel I ask for much. I know for a fact I ask for way less than what I feel they're capable of or what I think would be fair. But that doesn't mean I don't question myself. This is why I'm here. I hope to gain insight to the validity of my requests and gain perspective on how I may be contributing to the problem. To start I will list chores, expectations, and rules. The twins have about 15-30 minutes of chores everyday after school. These include taking out garbage, tidying their bathroom, and feed their pets (and pick up doo-doo). They are also expected to keep their room relatively tidy, which does not happen but hey they're teens and teens are gross. Once a week they both have a bigger chore where one does floors and one does some laundry folding. This may take 30 minutes to an hour or so. The little ones each have a chore too. The 5 year old cleans the living room floor which is mainly toys. The 4 year old tidys the shoe area. Total 5 mins or so each. That sums up chores. The rules and expectations: They need to keep up with their school work. And wake up in the morning for school on their own using the alarms in their phones. They can raid the fridge and pantry for anything healthy like fruit, yogurt, granola bars, etc etc. They have to ask for junk food. That's it. Now what actually happens is they do a quick lazy job on all their chores until I make them do them good. Ok. Again, they're teens. I expect this. The thing is, I can talk to the younger twin, and she'll say sorry I do it now or do it right next time. And she does. The oldest just starts off saying how I'm so rude and then she's crying and screaming how I'm just mean. This girl is the worst. She'll scream so loud her mom, my wife, will come down and immediately defend her daughter when it's her daughter doing this.  Cause of this situation happening repeatedly, I refuse to deal with her directly. I have been trying to get my wife to deal with her every time an issue arises and now my wife thinks I have it out for her. She thinks I'm hyper focused on the oldest. I find the younger twin crying all the time because of how the oldest makes fun of her at school in front of her friends. Or how the oldest will just blame her for things that are clearly the oldest' fault. Constantly belitteling her sisters. Constantly making fun of them. Especially if they show emotion like crying or sadness. She never apologizes, even when she's made to she finds a way to make it insincere. The little ones calm her the mean sister. The younger twin calls her a bully and a bad person. I try and talk to her trying to say she has so much good to offer her sisters but she chooses to make them resent her. I am starting to resent her because she just doesn't care. She doesn't care about anything or any of us... except for her little dog. She makes sure to say I love yous and hugs and kisses her dog in front of us all. I can't remember the last time she hugged any of us. Don't misunderstand... we hug her all the time. She just kind of leans in and looks away. She's always saying how much her dads is better than our house but he's a sexual debviant who propositioned his ex-mother-in-law to give money for sex and feet pictures. And he's a fucking flake who just is blowing his chance to be a dad to these children. Another reason I tend to take it easy on them when they are having attitude or blow ups. But again, the younger twin is reachable through conversation. The older ends up saying she wants to commit sui.. and hates me and wants to live with her dad. But if we let her live with her dad she'll end up a piece of shit just like him. So that's not an option. It was affecting me so negatively I pretty much begged my wife to intervene. She did a bit but when it comes to discipline or consequences, she does nothing. Now I'm begging again for her to intervene again because I found our younger twin crying in the garage. She was crying about being bullied and how if she does or says anything, her sister will make the cool kids at school be even more mean to her and make more fun of her. I went to my wife and she exploded saying I have it out for the older twin and she wants to leave. My younger twin doesn't talk without some prodding and my wife does not do that so they don't talk about anything real. I've begged my younger twin to talk to her mother but she says she can't. My wife is mad at me and I blame the older twin. Now I constantly wrestle with the guilt of having this resentment toward my daughter and my wife. I can't leave or the younger twin and the little ones won't have my protection, little as it may be. I need help. I am inching closer and closer to just losing my shit and making myself into the bad guy. Help.