Kristi Noem Officially Files to Divorce Husband Bryon

Kristi Noem has finally filed for divorce from her husband, Bryon Noem ... months after claims about his cross-dressing and wearing fake boobs surfaced.

The former Secretary of Homeland Security filed for divorce in Hamlin County, South Dakota, on Monday.

Kristi's citing the boilerplate irreconcilable differences. She also left the door open to ask for support.

We knew this was coming ... Kristi's mom -- Corinne Arnold -- told the Daily Mail back in July that the pair were headed for a split.

Back in March, DM put out a report which claimed Bryon took selfies while wearing oversized fake boobs and chatted with adult performers in the "bimbofication" fetish scene ... focusing on their massive fake breasts.

The report claimed Bryon told people he wanted "huge, huge ridiculous boobs."

Kristi's team later released a statement which read, "Ms. Noem is devastated. The family was blindsided by this, and they ask for privacy and prayers at the time." The former DHS Secretary has been linked to political operative Corey Lewandowski in recent months.