I didn't get to the end but I thought the statistics I did read were fairly interesting but not surprising.
In partnerships with very traditional roles, sex is possibly more frequent because you are being a bad wife if you decline and an unmanly man if you're not always up for it.
That said, the difference is only 1.5 times a month.
Having less sex isn't a bad thing if you are happier and more equal in other aspects of your relationship.
I gave up because I felt the tone of the article was criticising equality because it lead to less sex...and that's a negative, bullshit message I couldn't be arsed with. But, I didn't get to the end so maybe I'm wrong to say that.
The thing I read that surprised was women in traditional-role-relationships reported increased sexual satisfaction. Without knowing the method and sample size etc. I don't know what to think about this. But the cynic in me speaks from personal experience in saying that it's easier to have lower standards of sexual satisfaction when you are in a sexist/unequal relationship; you don't expect as much thus are pleased with the bare minimum.