Paul Marciano is making a major cut from his personal life ... because the co-founder of the fashion brand Guess has filed for legal separation from his wife.

According to the docs, obtained by TMZ, Paul filed for legal separation on Monday from his wife, Mareva Georges Marciano, after nearly a decade together. He cites the usual "irreconcilable differences" as the reason for the split.

The docs show the two share one child, 13-year-old Gia ... and Paul is asking for joint legal and physical custody. He's also acknowledging spousal support will be handled under the terms of the couple's prenup ... which they signed back when they tied the knot in November 2016.

Marciano made headlines last summer after Guess caught major backlash for using an A.I.-generated model in an ad campaign. Paul defended the move to TMZ ... saying he's always been drawn to bold ideas and saw A.I. as the fashion industry's newest frontier.

Back in 2018, Paul was forced to step down as executive chairman after the company shelled out $500K to settle sexual misconduct claims brought by five women.

Marciano resigned as executive chairman but stayed on as Chief Creative Officer to help with the company’s transition. One of the most public accusers was model Kate Upton, who accused Paul of inappropriate behavior during shoots and meetings.

The accusers alleged Paul groped them or pressured them into sex acts -- but four chose settlements over a courtroom battle while keeping the right to tell their stories publicly down the line.