Fault divorces still exist but they are becoming rarer. And even in no fault states things like cheating are still brought up at times in order to try to get a bigger settlement.
I'll just add on to this and mention that while many states are considred "no-fault" that only means that someone doesn't need to be found at fault as a reason to divorce. Every state that now allows no-fault divorces also still has "at-fault" laws on the books too.
Also, I'll mention that the trend is away from mandating spousal support. The laws and society as a whole are clearly shifting away from it but the courts are much slower in adopting (the same holds true for child custody in divorce cases).
Thanks for clarifying. I believe that the spousal support and child custody changes that are happening (often not quickly enough, though) in the court system are a result of gender roles changing. Used to be, women got alimony much of the time because, let's face it, earning capabilities were not as good and they were often/nearly always the children's primary care giver. All of that is changing, to the good, I think.