Many courts post court records online. If the divorce would take place in Denton County, you can look up court records at www.justice.dentoncounty.com under Family case records. Dallas County and Collin County also post court records online.
If the county where you believe your wife has filed for divorce does not have an online record search, you can contact the district clerk for that county and they can tell you if a case has been filed.
I think Flower Mound is in Tarrant County. If it is, you would call the Tarrant County District Clerk's office, ask for the Family Law office and tell them that you believe your wife has filed for divorce. You should find the Tarrant County Family District Clerk's telephone number on the county website. The District Clerk's office could at least tell if she has filed for divorce. The Tarrant County District Clerk's Family Division is located at 200 E. Weatherford, Ft. Worth, TX 76196 and the telephone is 817-884-1265.