I'd like to start out by saying I don't mean to be rude or imply anything, I am currently in a very ugly custody battle with my ex.
From someone that has been made out to be "that guy" you don't know the whole story, and never will. There are three sides to every story... When my ex first gave birth we split up, I was trying to see my daughter as much as I could (I was going to school full time and working two jobs). Plus every time would try and pick her she would want to talk and try and get back together with me. I wanted no part of her but wanted to see my daughter. So I got a lawyer, my lawyer actually told me we need to file for the moon and we will settle later. Additionally he told me to stop talking to her, paying for anything, and seeing her... 8 moths later I was grated visitation and worked my way to 50/50.
Fast forward a couple years, my ex abducted our daughter and drove her to Georgia to live out there. Had her a whole month before I was granted temporary 100% custody. Now she has monitor visitation and phone contact, because she decided she was going to "move back out here".
Long story short, documentation is key. Recordings, times, dates, people, places, everything! You can never have to much. Additionally this is not your fight, it is something your girl and her ex need to deal with. You really need to just be supportive and not whined her up about too much.
It looks like you have a great head on your shoulders and understand most of this already, but it won't be over quickly and it is going to be expensive. If in my case I knew the truth was going to come to the surface sooner or later, so we just had to let it play out and do the best I could to raise her. I have had a long time girlfriend through most of this, and she really never commented on any of. She doesn't try and be a mom, she doesn't try to tell me what I should do about things with my ex, she doesn't really even talk about her, she's never even seen or talked to my ex.
Sorry that was a whole lot longer than I meant it to be. There are others going through similar situations, so just remember you aren't alone.
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