Yes, you would need and pay for two accounts if both you and your spouse are going to file tax returns as Married Filing Separately and use the TurboTax online editions.
Or you can purchase one of the TurboTax desktop CD/Download editions and create two tax returns at no charge after purchasing the software.
See this TurboTax support FAQ for filing jointly versus separately - https://ttlc.intuit.com/community/married/help/is-it-better-for-a-married-couple-to-file-jointly-or-...
