Hi Sage7 and welcome to PC!
You posted in just the right place....no worries
Oh boy, it sure does sound like you all have your hands full with a rebellious teen. I've raised 2 girls, now 24 and 29. It wasn't easy and we too ended up with a blended family and a couple of step parents.
I have a couple of thoughts regarding your issues here. Fourteen is a tough age where the girls are struggling with self-esteem issues, the breakup of her parents, the marriage of her parents to other partners, trying to find herself and battling being a child and becoming a young woman, boundary issues, etc etc etc. (not to mention raging hormones *sigh*) Her world is topsy turvey to say the least right now. Does that give her the right to be mean? Oh hell no, but, I'm sure some real heart to heart discussions with her are definitely called for.
I'm sorry your wife is at her wits end and now taking all this on her shoulders and thinking she is a bad parent. Please let her know that even good parents have kids who rebel and cause hate and discontent as they are growing. This is not a reflection on her as a parent, but a situation that needs some drastic attention.
If mum and daughter could spend some quality time together, just the two of them so they can have some fun, have some girl time, go shopping or out to have their hair done or even a walk in the park together, it may help tremendously. I wonder if your teen is feeling as though she is being ignored or her needs are not quite being met so the only attention she gets is when she does negative things?? I could be way off base here, it's just a thought. So many times we parents get caught up in the day to day hassles and forget to give positive re-inforcement to our kids daily.
Maybe when your teen is in a good mood, you can all sit down together and draw up the rules of the house with her input. Working together and listening to each other through this process is important for her to take ownership in being a productive familly member.
Maybe it's to the point that there is no patience between mum and daughter anymore. If that is the case, then I would suggest some family counceling. Getting everyone on the same page can be difficult at times and counceling can help the situation.
Just some thoughts thrown out for you. I don't know if they are relevant to your situation or not, but I hope they are helpful.
I wish you all strength and love as you work through this process. Best of luck to you all!
Hugsssss
J