I agree. I don't understand it, but I believe it. But it's deeper than that (MOO):
To those that doubt it could happen: it happens all the time. There exists mothers/wives do NOT see it, can't see it, can't believe it. They can be beaten nearly to death, beg family members not to blame the perp, and think they deserved it. And because they think the flaw is within themselves and not the perp, they don't think that the perp will hurt anyone else. And if he (or she) does, then obviously the person must have done something to trigger it and so if they just behave in the future, then it won't happen again. So the abuser is perfectly safe to be around b/c he (or she) is okay: it's everyone else who is 'asking for it'. THAT is the mentally of someone who has been abused... (whether the abuse is physical, sexual, emotional...)
It's hard to believe if you're never seen it.
ETA: I don't know if this is what is going on with Billie, but I suspect it is something very similar.