Personally, I don't think that in any society (wizarding or otherwise) divorce should be made completely impossible. It just seems very unrealistic.
If it is absolutely essential to the story, I would make it just extremely rowned upon to even consider divorce. Even in Victorican times (which the wizarding world seems very close to), divorce happens and
was possible, but it was just very, very uncommon and very, very frowned upon.
Hope this helps!
- Cammie!
