I just drafted a stock purchase agreement for my business partner and I on our new startup and one of the basic boilerplate additions to the stock purchase / vesting agreement is a spousal agreement to the terms of the purchase.

The communal property law only relates during a divorce were the shares are split up between the couple by the courts. Any decently written stock purchase agreement has a first right of refusal for the company to purchase back those shares in the event of an involuntary transfer.