Jessica Simpson's Mom Files for Divorce

Jessica Simpson's mother Tina has filed for divorce from Jessica's dad Joe.

Tina filed the papers in Texas last month, claiming, "The marriage has become insupportable because of discord or conflict of personalities."

Tina and Joe were married in 1978. They have no minor children.

In the docs, obtained by TMZ, Tina claims she has separate property from Joe and wants to keep it. It's unclear what that property is.

In the county where Tina filed, there are specific rules about how divorcing spouses have to behave toward each other during proceedings -- they can't curse at each other, harass each other over the phone, or physically attack each other ... basically they HAVE to act like civilized adults.

If one spouse violates the rules, they could be found in contempt of court.

Joe filed a response to Tina's divorce petition days later, insisting Tina get nothing from the split.

Joe and Tina both played a pivotal role in turning their daughters Jessica and Ashlee into pop superstars.

A rep for the family just released a statement, saying, "It is an amicable split and there is no third party involved. Any other related allegations are completely false. The family appreciates your respect for their privacy at this time."