custody battles

hello fellow step mamas...

posting anonymously just in case

my husband has a 10 y/o daughter(going on 11 in sept) and we have a 3 month okd daughter together.

My husbands bm is married with a little boy who just turned 4 with her husband.

My husband and his bm have joint custody, 50/50 time, and equal decision making. the only thing mom has is final say on medical decisions.

We have always had to fight with her over parenting my step daughter whether it was over parenting time, decision making, school projects and homework, you name it im sure there was an argument over it...it got so bad that i eventually had to get a restraining order on her because she was upset that we didnt take her to a soccer game(she was grounded at the time) when it was our weekend and tried to break into our house(while i was 7-8 months pregnant mind you) to get her.

My step daughter’s mother is nothing but emotionally and verbally abusive to her(as we’ve learned to record and document EVERYTHING) so at this point in time we have decided to take her to court for sole custody. we arent trying to take her away from her mom(we would like to keep the schedule as close to the same as possible) and we have expressed that to my step daughter many times..however her mother is very manipulative and will say “they’re trying to take you away from me and you’ll never see me or your brother again!” in attempts to put her in the middle of it all(which no 10 year old should be).

I guess what im asking is, has anybody else gone through custody battles? what should i expect? Our state is a mom state but with all the evidence we have, should we expect to win? what are your experiences?