Jaime King's second husband, banker Austin Sosa, is withdrawing from their marriage ... because he just filed for divorce.

Austin beelined it to court Thursday and filed to divorce Jaime ... according to online records.

The reason for the split is unclear ... but the divorce filing comes just weeks after there were reports linking Jaime to another man, hotel owner Vikram Chatwal.

For her part, Jaime reportedly denied she was seeing Vikram, insisting their hangouts in Los Angeles were all business ... but that didn't stop Austin from pulling the plug.

Seems Jaime and Austin got married in a secret wedding ... no one even knew they were hitched ... back in July, reports emerged that Jaime and Austin were engaged.

No word on a date of marriage or date of separation because the divorce docs are not available yet ... we're working on it.

Jaime and Austin did NOT have any kids together ... so no child custody or support issues to hash out here.

It's the second divorce for Jaime ... in September 2023, she finalized a nasty divorce from her first husband, Kyle Newman.