Both positions have legal support depending on jurisdiction. In community property states (California, etc.), the default rule without a prenup is:
- Equity vested before marriage = separate property
- Equity vesting during marriage = community property (because your labor during marriage caused the vesting)
- Appreciation of pre-marital equity due to your labor during marriage = community property to the extent attributable to community effort
Common prenup approaches for startup founders:
- All equity stays separate: Simple but your fiancée gives up potentially significant value if the startup succeeds during the marriage.
- Pre-marital equity = separate; marriage-period vesting = community: This is closest to default law and often feels fairest.
- Sliding scale: Your fiancée gets an increasing percentage of marriage-period equity based on length of marriage (e.g., 10% after year 1, up to 50% after year 10).
Whatever you agree to, BOTH parties need independent counsel for the prenup to be enforceable. Budget $5K-$10K total for both attorneys. Worth every penny to protect an $8M+ interest.