Hi. I am new to this, but I am in need of some kind of "therapy" (if you will). I need to validation or advice on my issues.

I have been married to my husband for 2 1/2 yrs but we have been together for 6 yrs. I have known his daughter the whole time. He has primary joint custody. Anyway, I have 2 daughters 15 and 9 and for the most part they all get along. The issue is, anytime my husband and I have a "family meeting" to discuss how things are going, SD14 feels she needs to justify or rebuttal to all I have to say (w/ attitude "neck roll" in all). I find it very rude and disrespectful. She has raised her voice to me once before and her dad grounded her. He trusts my judgment in what and how I talk to SD14 and allows me to correct or stop her when this happens. SDs BM doesnt help either, she tells her daughter that I need to give SD14 respect BEFORE SD gives me respect. Now the way I see it is, SD is 14 yrs old, lives under MY roof ( I have had my home 10 yrs prior to meeting my husband)I am helping care for her physically, financially and emotionally!!! My own kids dont even think t rebuttal to anything I say, because they have learned the hard way! SD lives with us because her mom is a deadbeat mom, doesnt have a stable home, no job, no stable relationship, and has a BAD attitude and under minds all our rules, expectations and requirements! Now SD has ALL she needs and wants with us, but then goes to her moms every other weekend and gets to do WHATEVER AND I MEAN WHATEVER she wants with her mom (she has her cake and eats it too).

I am at the point where sometimes I think about a divorce because this has become so stressful. What should my role be towards SD???? Please any advice will be helpful!