If a divorce were to occur and the QSBS was divided between the two individuals it would be treated as if each individual had QSBS from the day it was issued. The divorce actually creates two separate exclusions, one for each spouse. For example, each individual would have their own $10 million or 10x the initial investment exclusion. The 10x exclusion would be smaller (because the initial investment would be split), but each individual would have at least a $10 million exclusion.
This article does not constitute legal or tax advice. Please consult with your legal or tax advisor with respect to your particular circumstance.