Yes, that is allowed. Employers who do not offer health benefits to full-time workers could face a penalty, but they will not face a fine for failing to offer health benefits to employees’ spouses. Employers are required to offer health benefits to dependent children (i.e., children under 26 years old). The penalty and requirement to provide health insurance coverage to dependents does not apply to employers with fewer than 50 employees.
If your spouse is not offered health benefits through your job, s/he may be eligible to apply for coverage and premium tax credits through the marketplace. (26 U.S.C. § 4980H; 42 U.S.C. §300gg-14).