Do I need to be on the same health insurance plan as my spouse?

No.  There is no requirement in the Affordable Care Act that spouses be on the same plan.

However, if you want to qualify for a premium tax credit to lower the cost, be aware that subsidies are based on your total household income level.

So, even though your spouse will not be covered by the subsidized insurance plan, their income will be calculated when determining the level of subsidy for which you are eligible.