without writing a book about it, the simplest way to explain how it worked for me is that if something sd does or says, even if it pisses me off, if it has no affect on my kids or me, i don't say a word about it. fdh lets her skip school at least once a week when she fakes being sick, it's not my kid who won't graduate, so i don't say anything about it. if he lets her spend the weekend at her bf's house after spending the whole week being a disrespectful little bitch and not doing any of her share of chores, it isn't my kid who is going to go out in the world and think they can whatever they want without working for it and treating people decent, so i don't say a word.

she calls my infant son a butthole or douchebag, that affects him and me. you're damn right i said something! that's how it works. stop taking responsibility for teaching her anything. let her fuck her life up, let fdh allow her and even help her do it. but when she gets in your way, that's when you stand up for yourself and make sure you are heard.

I try to think of skids like I do neighbor kids. I don't approve of may things they do, but not my problem to teach, train or discipline them.
If I see a neighbor kid in the street about to be hit by a car, I would do something.
If I see a neighbor kid, downing 5 pieces of birthday cake and a 2 liter of soda at a party, I think; Wow. what parent raises a kid that way, but I say nothing.
If neighbor kid hurts or bullies my kid, I put a stop to it by letting the parents (or DH) know that I will not allow that to happen in my home, yard, or neighborhood.
This has worked for me for 14 years. I am much happier than I was the first 2 years of my marriage when I tried to parent skids with miserable results.

she sounds a lot like how sd19 was when she lived here. this is what i would do. if she refuses to speak to you, don't speak to her anymore, either. let her leave without a word. it's not your job to know where she is or what she's doing.

if dh wants to pay for her shit and won't stop doing it, get a seperate bank account and let him pay for it out of his own pocket. if you don't have an income, this affects you. speak up. ask him how he would like it if you were paying for your brother, sister, mom, dad, bff, neighbor, whoever's car insurance. if she isn't willing to pay for it, she shouldn't have it. she has no job? she's in your house and this affects you. tell him to get on her ass or get on it yourself. don't cook for her, do her laundry, nothing. dh is not doing her any favors by letting her be a leech. if you can seperate your money, split bills 3 ways (if she's over 18) and give him 2/3 to pay for. if he won't do it, let things like cable and internet get shut off. he needs to know you're serious.

i know it's hard to keep quiet when you're being lied about, but you have to try. don't let her stupid blatting mouth control you. let her run it. let her lie. who gives a shit? you just keep on being you. if you want to confront her about what you've heard, you can do that. i've done it with smil. or you can just ignore it, because her words have no power over you unless you let them.

i do understand how hard it is. i've struggled with all of this. but letting it go and not letting it be your problem anymore is so freeing.