On the relationship between Mr and Mrs Many-Names.
I am wondering if there is a huge degree of coercive control going here. Whenever they met, and whatever name he was using, she was in her teens and he was older. Potentially up to 10 years older. We know he has a loooooong history of targeting and manipulating women he perceived as vulnerable. Why would we think young Diane would be anyone different? So he marries her, then moves her around Europe, UK, Tasmania, various parts of mainland Aus. She doesn't work - perhaps she is his "carer" perhaps he won't let her. She's never anywhere long enough to put down roots, make friends. As soon as she is getting into community things through the kids, he's up and moving them off somewhere else. The kids grow up, leave home in the late 90s. She's now in her 40s/50s, no friends, no work history, no support network. She's perhaps had 40 odd years of him telling her that she's thick, useless, who would want her anyway, no self-confidence, no option but to stay with him and turn a blind eye to his goings on.
I'm not saying it happened. But I am saying that having seen it happen to a friend who went from being a confident and happy teenager to utterly dependent on a horrible controlling husband that it could easily have happened.
She has one name change only - and that was from her birth surname to her married surname. Had she been an accomplice, she'd have been changing her name too. Or he'd have been changing it for her. I got the impression of her as "the little woman at home", totally in thrall to her husband and beaten down after being told how useless she is and how she's lucky to have him for 50 odd years.
