The Board of Directors appoints officers. It is not clear from your question whether you and your husband are the only Board members. The majority of the Board needs to remove the Secretary unless the Secretary's term expires. I suggest that you consult a business lawyer. Give him copies of your Bylaws and recent minutes of your Board. There are many possible facts that need to be examined to give you a good game plan. I also suggest that you ask him to resign. He might just do it and save you the trouble.
With shares being split 50-50, you are in a deadlock: You have and will have 50-50 control over the board, which appoints and removes officers. There is no way to force the secretary out.
Why do you want him out as secretary? He still will be a shareholder and a director.
Given that you are going through a divorce, perhaps your respective lawyers can help you achieve an acceptable solution to this problem now, rather than having to wait until the divorce is final.
This information does not constitute legal advice and does not establish an attorney-client relationship.
As my colleagues point out, the Board appoints, not elects, directors and is the decision maker about firing officers. Since the Secretary does actual little work (other than minutes of meetings) there may not be a big issue here. Removing a Director would be a big issue.
The above is general legal and business analysis. It is not "legal advise" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.