So all good food for thought, thank you!

Hopefully I can answer all th questions, fill I the holes...

Last January, the oldest daughter (13 at the time) was grounded from her kindle. My fiancé gets his kids every other weekend and tries to let her have her space. So she was in her bedroom alone. He knocked on the door and went in to ask her if she wanted to watch a movie in the living room, saw the power cord and took her kindle. He's a 350 lb guy so usually there isn't any challenging him, but she lost it. She got up (she's 220 lbs at 13 years old) and started hitting and scratching to get the kindle back. He called his ex while she was still attacking him. He put his hand out to push her away and she kept coming at him... with palm flat out she pressed her upper chest/lower neck against it so hard, it left a bruise. So many problems stemmed from that bruise.
After she calmed down, my fiancé saw she had been talking to adult MEN on an app called kik. He sat her down (and his son who didn't understand what was going on and tried to step in the middle of it) and explained online sexual predators and how men will say anything to get pictures and more... it was a long, very descriptive talk. That was a Saturday. Sat night everything was fine, Sunday everything was fine - and we dropped them off sun night. He then got a call sun night from the mom saying there were bruises and he explained what happened.
Long story short, the kid lied and said her dad choked her - because she was mad she didn't get her kindle back. The crazy ex believed her even though he'd never done anything like that before and filed child abuse charges against him. And filed an order of protection for him to not see or contact any of his kids. The courts sided with her and he didn't see any of his kids for 9 months. We were in court a lot fighting this. The charges against him were dropped and the detective told him "off the record" he could tell that the ex was very manipulative.
After 9 months of fighting in court, we got them back and the very first weekend, the oldest asked for her kindle back. He gave it to her willingly, and for Xmas we got her a new one. Just hours after giving her the new one, he texted the ex telling her what we gave all three kids and she said to take it back that the oldest was not allowed anything that goes online and she'd explain later. So my fiancé takes the kindle away, no fight this time. He looks at it and she's downloaded kik again and has 17 different conversations going with men several sent dick pics and asked for pics of her. He had the talk again, and took the kindle to the police station to report the men for sexual misconduct with a minor. The ex called him later that night and told him that she had gotten the three kids one iPhone to share and the oldest had been caught texting her cousins husband and apparently their texting turned into a relationship. The ex said charges we filed but when my fiancé asked more questions the ex said she didn't want to talk anymore about it. This all happened during the time we weren't able to see the kids. And the ex isn't forthcoming with info, doesn't answer her phone, and isn't there when we pick up or drop offf the kids to ask more info. So we literally have no idea if the guy is in jail or not (irony is he was a corrections officer in a jail). The ex told us about a month after Xmas that the oldest found her kindle in the garage and did it AGAIN. Seriously this kid does not learn. The ex said she was in therapy but I have no idea if she still is.
He's worried she'll get mad at him again and say he did something he didn't do and won't get to see any of the kids again. So that's why he's so lax now.

The oldest randomly decides to not come over on his weekends - and it is so pleasant when she's not here. The kids clothes didn't fit them - their mom (the ex) spoils the oldest and doesn't buy the kids new clothes. I second hand shop for financial reasons so we brought the younger two (7year old girl and 12 year old boy) shopping to get them some clothes. We did second hand shops and some clearance shopping at Jc penny. I picked up two pairs of pants while shopping for the oldest who didn't come that weekend. Both were from second hand, both were name brand, one was new with tags from lane Bryant. I really didn't think it was that big of deal, I was trying to include her even though she was not wanting to be there.

A little more background - the ex lived with her parents until this year (the exs parents bought her a house this year but the ex won't tell us where she lives and we pick up and drop off at the grandparents house still). The ex was in a bedroom with the oldest daughter, the youngest daughter and a fourth child she got preggers with while still married but doesn't know who the father is - it's a different race so obvious it isn't my fiancés. But that poor fourth kid doesn't have a father who visits him and I feel so bad for him. My fiancés son had to sleep on the floor in the living room in his exs parents house because the grandparents each needed their own bedroom and so no bedroom for the 12 year old boy. Ridiculous - they wouldn't even let him sleep on the couch because they didn't want him sweating on it. They lived with them for 2 or 3 years like this. CPS was called but the kids were told to lie or their mom would get in trouble so they lied for their mom.

The oldest daughter is very bipolar and every day is different. Because she wants a friend to spend the night tonight, she's acting like a great kid... as soon as it's over I'm sure she'll be back to being hateful.

I love this man so much and he treats me so great and I can't imagine being without him. His daughter though... I can't believe she would be willing to lie to the police and have his rights taken away from him (and possibly ruin his life with the child abuse charges as he's going to school to be a teacher) just because she can't have her kindle back. That is pure evil.