I guess where I disagree is that the working parent presumably benefits from the non working parent’s labor. They decide together how their lives look, agree together that less income is worth it for the other benefits of the person staying home, and then afterwards the partner who stayed home has permanently lowered earning potential. Those are fine decisions to make together, but if you split up, the parent who kept working financially benefits and the other is fucked. I don’t think the goal should be to maintain the same lifestyle, because that is going to be impossible (though if there are kids, their lifestyles should change as little as possible), but trying to equalize their changed earning potentials makes sense to me.