My spouse and I have been living in different states for the past 7 years. From what I hear she lives with a man in St. Louis and has a child with him. How can I file for divorce from the state of Texas. I have no address on her and can't find one.

You file where you are now living, not where you were married.

You will need to try and locate him, but each court has its own standards on how and what they require. Easiest way, hire a local divorce attorney who will file where you live.

Commonly, when a spouse cannot be found, notice of the petitition for dissolution being filed is published several times. If there is no response to the publication, the attorney moves the court to set a date for default prove-up (the hearing when everything is finalized). If the judge agrees to the default prove up, they finalize the divorce without the partner being involved. The court may reserve determination on some issues, or may rule on everything. You need a lawyer because you must meet all the requirements completely to get a default ruling. If a spouse cannot be found, I've seen divorced go very quickly and easily.