If you and your spouse get different fingerprint dates, then go together on the same day. Most likely you both will be printed same day.
If you and your spouse get different interview dates, then if the dates are a few days apart (<5), go together and ask if you both can be interviewed same day. Most likely it can be accommodated. The only factors mitigating this are if the Service Center is too busy or if one of your case files has not yet arrived at the Service Center. The Service Centers generally have all the case files for all applicants in a given week. So if there is a two week difference in time between your spouse and you for interview date, the Service Center most likely will be unable to accommodate.
If you and your spouse get interviewed on the same day, then there is an extremely high probability that you will have both your oaths on the same day.
You and your spouse cannot attend the actual interview session with the officer together. The officer will interview you both separately.