I’m not sure about AVS, but 2nd and 3rd are split unless a prenup says otherwise.
More about that topic in this thread: Marriage types and divorce splits
For this reason, a prenup is the right way to go.
Ideally, one does not rely only on AVS, 2nd and 3rd pillar. It also makes a lot of sense to make sure that both spouses work in equal parts after the wedding (something I continuously advocate in this forum 
).