My Spanish is not that good, but I think I understand that bit
Yes, German family law was changed in 1977 in West Germany. Until then, if a wife had a job somewhere, her husband could ask her boss to fire her if he thought she did not sufficiently attend to her home duties. In 1977, §1356 BGB was changed to "Die Ehegatten regeln die Haushaltsführung im gegenseitigen Einvernehmen."
The GDR didn't have any such discrimination. It also had traditional role models of wife and husband, but there were no stay-at-home mums because all women had a job.
I don't think that's the kind of Hausfrauenehe the author really had in mind, though. It simply occurred to her that spending time with her child might be beneficial for her child - an insight so fascinating that she had to write an op-ed about it and wants people to pay for it :>