Kimora Lee Simmons is going through her second divorce ... because her estranged husband just filed to officially pull the plug on their marriage.

Tim Leissner, an ex-Goldman Sachs banker, beelined it to court in February and filed to divorce Kimora after almost 12 years of marriage ... according to legal docs obtained by TMZ.

In the docs, Tim goes with the boilerplate "irreconcilable differences" as the reason for the split.

Tim does not list a date of separation ... the docs say TBD ... but we know they have been estranged since at least March 2022.

Kimora and Tim have one child together ... 11-year-old Wolfe Lee Leissner.

Tim is asking for joint legal and physical custody of their kid ... plus spousal support.

Kimora and Tim tied the knot in March 2014 ... and years ago, Tim admitted in court to faking divorce documents in order to marry Kimora while he was still married to his then-wife, Judy Chan.