Tracking down my ex to serve him divorce papers?

You will likely need to apply to court to obtain an order for “Substitutional Service” by way of serving a relative of his, or publishing an ad in a newspaper, or posting documents on a public notice board at a courthouse etc. You will need to prove what efforts have been made by you or a process server to do a search and locate in an attempt to find your spouse before the court will consider granting a substitutional service order. You can apply to court to obtain “Indigent Status” in which case the court can waive the filing fees involved in getting a divorce.