While I can see hedging your bets by having your spouse work a normal job (and possibly get you on their health insurance), if a failed startup is going to doom your marriage, your marriage is already doomed.
Also: if your relationship is strong, and the working relationship is hurting the personal relationship (or vice versa), one of the two will just find another job. People change jobs for their relationship all. the. time. --- for instance, almost every time one spouse wants to move out of state for a better job.
While I can see hedging your bets by having your spouse work a normal job (and possibly get you on their health insurance), if a failed startup is going to doom your marriage, your marriage is already doomed.