Confusion over "coverage" offered by my employer for spouse

I am offered healthcare through my employer at a discounted rate, but I don’t want an HMO through United. I have needs for specialists and hear United is terrible. I would rather waive my subsidy and go through the Healthcare Marketplace.

When filling out a healthcare.gov application, we are asked if my spouse is offered healthcare through my employer. My employer would not pay anything toward my spouse’s premium, but technically I could have added them to my plan.

Does this mean that my spouse is “offered healthcare through my employer,” or not? If the coverage isn’t subsidized by the employer, what makes this offer different than any other private insurance offer outside of the Healthcare Marketplace? When my spouse indicated he is not offered coverage through my employer, this would allow for him to have a subsidy and save us ~$400 a month. If he says yes in the application, he is not eligible for any subsidy, even though my employer wouldn’t help cover any of his costs at all. Help!