I am newish here and have posted to many of the others here so I thought it was time I start my story and get some advice....

I am a disabled mom...many yrs as a professional...unable to work due to the injuries...so now i am a stay home mom (aka broke and in pain...not the life I had before)...I have 2 beautiful bio daughters one in college and one in middle school(this daughter has developed many medical issues that have so far been undiagnosed...added stess to my crazy life)...I also have 3 skids...one daughter in college out of state...there is a good relationship with her and me but she doent contact dad much? but does FB/text/call me often...BM is gay and not a real prob now that daughter is grown...there is one son who lives from place to place out of state and is a really sweet kid to me when he is here but is just like his BM and dropped out of school and is on the edge of troube all of the time...we have spent $$$$$$ on legal fees to bail his butt out of legal trouble not to mention that BM NEVER paid a dime of CS EVER!!! We have had many legal bills for this son due to the BM's bs over time and his actions/choices...he doesnt call his dad unless he needs something...but he is really not a bratty Skid...he hugs me and is very thankful for the things I have done for him I feel he really does love me...he is good with his step sisters and his older sister but dislikes his younger half sister...(states he "hates her" for how she treats me and he treats her liks she doesnt exsits) he's just at the age where the future hasn't hit him and he is making bad choices...(breaks my heart) I was primary Mom to him from ages 9 to 13...and off and on over the high school years...dont have enough contact to give this son guidance...
THEN there is SD13!!!!!! The spawn of a psycho B$och!!!!!!!!!! This child has been with me since she was 3 yrs old and I have been the only "real" mom she has ever known...I opened my heart to this child and really really have tried to love and raise her as my own....this kid has caused me so much pain and hurt that I am at the point of leaving her dad (my DH x almost 8 yr) (lived together 10 1/2 yr now)...I can not begin to list the things this kid has done and tried to "get me out of her life"...she has many lists though... She is so jealous and full of hate that others can SEE her look at me and THEIR blood runs cold! They can see the hate this kid has for me....I have never ever in my life dealt with anyone so MEAN!! She is just so hard for me to deal with...I am loosing my grip over her and her behavior...she does have a list of psych disorders that come from the BM and the abandoment this kid faced at a young age...so I do try very hard to understand...BUT I am really at the end! We have been in therapy for years and years (started @ age4) but she refuses to try or to even "be nice" to me....I pray a huge amount over this kid and try loving her and accepting her as she is so I can help her make the best of her life...I just can't break through....It is so hard....she is so so so unlovable and MEAN!! She has written death threats to me, has called Child Protection, and she LIES LIES LIES...She is so onesided....it is unbearable...The psych dr and therapist are alwys tellig me that the kid is a real nut and that she may never change...and to not let her actions ruin my life and the life I have with DH...(Now that a hard one?!?!?) I just need advice on how to handle SD13 and the way her dad (DH) treats her...HE parents with GUILT because he KNEW that BM was a NUT CASE and he KNEW BETTER than to get trapped into a loveless marriage with her....He was ready to make her move out when she came up with the "oh im prego" (all the while telling him she could never have children!) Needless to say this marriage ended in a very violent way with the BM locking herself in a bedroom with SD as a baby and cutting her wrist infront of SD...screaming...Im killing her next and it's all your fault" baker act and dad got custody from all of this psycho behavior....unfortunately the BM got some unsupervised visitation with the SD off and on in her early elem years...the BM has since left the SD life after the court told her they were coming after her for filing so many faulse child abuse reports against me and for coaching the SD into lying to the officals... she's been gone 5ish years...too late though....the bad seeds have been planted...
I am now stuck with a real pain in the butt that makes my life hell if she can and lies lies lies....she is so mean and nasty...she acts out when she doesnt get her way by urinating/pooping on herself!! She does have psych issues but she can pick and choose her actions very well at school and saves her nasty behavior for our home.....I have tried the disengaging thing and it is very helpful...I have demanded that DH pick up his role and RAISE his BRAT!!! This started off pretty good but is now going downhill and I am so frustrated....I need you all's help to help me sort out my feeling and what to do.....I dont want to give up my life, DH and the stablilty that my BD's love...they love their StepDad and the other Skids...just not this one...she is really unlovable....soory but that is how I feel....:( help please....