Yes, that is probably allowed. Large employers (with 50 or more employees) who do not offer health benefits to full-time workers and dependents under the age of 26 could face a penalty, but they will not face a fine for failing to offer health benefits to employees’ spouses.
If your spouse is not offered health benefits through your job, they 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.)