My W did have a messy childhood as mentioned earlier. I was the only one who was always there for her. I defended her against her own father. I defended her against my family in her presence. I don't think W felt comfortable confiding in her own mother. I don't think she completely confided in anyone, just little pieces here and there.
W was picked on in school, a lot! Even by her teachers. Her mother did nothing to help her out, nothing. It's sad.
I saw some of this when MIL watched my children. My parents would interact with S11 & D9, MIL would not, she would go hang out in the kitchen all day. Still that way now. MIL will yell at the kids, tell them what to do, do stuff for them, but not interact with them or teach them things. Anyone who has studied parenting knows this is not a supportive way to raise children.
It is ironic how I notice now that what I feel for W is just like how I feel about D9. It's not that I "chose her because I loved her company" it's that I was in fact a caretaker. That it was my duty to care for her. To teach her right from wrong. That I needed to help her plan things, that I needed to be a good example for her and hope that she followed in my footsteps. That I needed to provide for her because she couldn't handle it herself. Some things I forced her to deal with on her own, like cooking, and deciding what to cook. She struggled with this one every single day.
Ironic, right after BD I panicked... Because I lost "control" over her? I don't know... I came up with it on my own at that point that I wanted control to try to prevent her from doing something really stupid, or something unforgivable.