Yes, it is very tough, but you said it right......two kids and one teenager...and you are the parent! This can be true when it is a WAW but I think it may be even worse when in MLC b/c the "experience" usually lasts longer if MLC.

Since you've brought it up.....let me say that you will have to continue to be the only mature parent the home has. You may need to think about sitting your W down and telling her that if she cannot stop taking sides that you will be in charge of the discipline until she grows up to be a rational adult. If you don't and she continues to treat S9 like this, you will have more problems coming that you can shake a stick at! I doubt she is going to overcome her self-centeredness enough to be much help for a good while.

Have to go, but will talk later.

It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!