Marriage is that relationship freely entered into in which each party vows for ever to put the other first. You can't do it unless you are in love with each other and the key is to make your love for the other a moment- by- moment decision (yes, decision).
In this light, qualifiers like "traditional" are irrelevant. The central truth of the marriage relationship hasn't changed and never will change. If the relationship is unequal it has already failed and been replaced by something else.
As for imagining that marriage could ever be "a business-like enterprise, a cool-headed agreement for running two lives in parallel", that is not marriage.