I think the article makes it clear that it is an intact family.
Now, I suppose the WSJ author will be chastised for using the term mom when referring to 1/2 of the family unit (excluding the children).
Actually it doesn’t make that clear at all.
It states that 85% of married SAHM’s do it for the family’s benefit. That doesn’t mean that 85% of SAHM’s are married.
It also indicates an increase in immigrant SAHM’s. Most of our immigrants are Hispanic. And out of wedlock births are out of sight in that community.