I objected to that figure, because you attributed this behavior to married couples. I read your link and none of the studies gave that high a figure for married couples, only for all pregnancies. Also, the studies were conducted in ultra-liberal European countries as well as the U.S.
Given today's promiscuity among young people and Europe's wholesale rejection of religion except among its Muslim immigrants, I do believe this figure is possible when applied to all pregnancies in Europe and the U.S., certainly including poverty communities such as "trailer trash" or "urban youth", as well as those marriages that took place when, or because, the bride was pregnant.
But I do not believe it could be accurate for couples who marry and wait to have children after marriage. One of your sources also cited the lower incidence of "cuckolding" among the more educated couples.
I doesn't surprise me that high-status men are cuckolded less. It's a good female reproductive strategy. Get the best schlup you can to support you and your kids and then populate the nest with better genes than the schlup can provide. But if your man is at the top of the totem pole, that strategy doesn't help. QED.
That's life in a fallen world.