Answered on Feb 16th, 2016 at 12:57 PM
It all depends on what you mean a complaint. If you mean a complaint with the Utah State Bar for ethical violations, it is my understanding that you can. If you mean sue the attorney for acts that have caused you problems, or loss of property or rights, probably not, as that person is not your attorney and owes you no loyalty.
However, it the divorce is pending in some way, you may be able to seek attorney fees against the person for inappropriate filings, and the like; or perhaps obtain a restraining order or injunction, depending on the facts of the case.
You really should review your case, and the facts, with an experienced family law attorney who also knows about legal malpractice. I have handle both types of cases.