Perhaps because in the Jewish world it is the mother that provides most of the education to her children and the husband should be working to support his family. Whatever is said, the fact that a husband works goes back to Adam harishon and it wouldn’t be “healthy” for the couple if the husband spent his days at home. If you mean while your husband would be learning, how long would that be already? And if it clearly will be a money issue, maybe learning shouldn’t be an option.