Generally speaking, I completely agree. But in this particular case, she really kind of reined him in, as in gave him a lot of the stability he was looking for and showed him a lot of the support he needed, having grown up in a massively abusive household and such. Also, if you see them together, it's clear that she's wearing the pants in the family and he seems quite happy with that. But when it comes to age gap relationships, this is really the exception rather than the rule.