Advice on couples pooling finances

This might be against rule 7 but what the hey. Me and my wife pool all our money. We have separate personal accounts but all salaries go into a joint account and then we pay ourselves an equal personal allowance from there. All other expenses, savings etc we manage from joint. From my experience this seems to be unusual. The norm seems to be each partner pays some amount into common expenses, and keeps the rest. If both people are earning similar amounts this works out approximately the same as us in practice, but I also see it happening where e.g. the husband is earning double what the wife earns. I cannot get my head around this, it just seems guaranteed envy, animosity, divorce. So I'd like to know what people see as the benefits of this way of managing things, or alternatively the downsides of our arrangement. Kinda worried I'm missing something