"My husband flew, so he would not have to miss my birthday."

Translation: Mia edzo flugis por ke li ne devu maltrafi mian naskiĝtagon.

[Jamthom8]

Does anyone know of a good explanation for "por ke" and when to use it?

[mihxal]

"Por ke" is used in similar situations like "por" but "por ke" introduces another clause.
https://adventuresinesperanto.wordpress.com/tag/por/

[Mark721417]

I had expected 'devus', is there a reason to use 'devu'?