I said put less emphasis on SD17 being the CAUSE of the marital problems. That's "WTF".
As far as DBing SD17, if she's 2 months shy of turning 18 and will be leaving to go out on her own, then I suppose you won't have to have any contact with her... Of course, if you want to be in his life again, it's going to be up to you to at least be the one that extends the olive brance since you are, after all, the adult and she's just ACTING like she's grown.
I also have a stepdaughter from hell. Same age, too. Fortunately, her grandparents raised her and not us. Or maybe not so fortunately for her since I'd have knocked her head off before she turned 12 but I'd have also structured her life instead of letting her run it and everyone elses. I sympathize with you as far as what manipulative brats (not my first word of choice, either) these girls can be however, that doesn't change the fact that it's on you to suck it up instead of coming off like a brat yourself.
There are resources at the top of the MLC forum where you can get a lot more info as to what MLC is all about. Just because someone wants adventure and is enjoying independence does not mean they're in MLC. It could just mean their marriage sucked. If that's the case, what part might you have played in that? Make no mistake, it took the two of you as well as SD17's "help" to get in this condition but someone has to have the balls to face the facts and so far it doesn't sound like he's got the tools for the job.
I'm betting you do and before you go getting your panties in a knot, that is actually a compliment.
