TX is one of the few states that still allow a common law marriage to be formed within their borders. If a common law marriage in TX is legally formed under TX laws, the other states will recognize that marriage. The states will generally recognize a marriage that is legal in the state in which the marriage was formed; the only major exception is same-sex marriage. Many states do not recognize a same-sex marriage even if it is legal in the state that formed the marriage. (TX is not one the states that currently allow same-sex marriages to be formed.).
You may want to check with a TX attorney to see whether the alleged marriage is legally recognized as a common law marriage by TX.