In Texas, a couple is married until the day they get divorced.
We do not have “legal separation.” Therefore, even if they have been separated for years, they are still married.
To modify the amount of child support (either an increase or decrease in the amount ordered), one of two things must be proven in court: either (a) you show that the circumstances of the child or a person affected by the order have materially and substantially changed since the date the order was signed; or (b) it has been three years since the order was signed and the monthly amount of the child support award under the order differs by either 20 percent or $100 from the amount that would be awarded in accordance with the child support guidelines.
Most cases will fall under the three-year category, so the question of whether child support can be modified becomes primarily a question of math.
If a divorce from a common law marriage is not brought within two years after the parties separate, then there is a rebuttable presumption that there was no common law marriage.