Mary Kay Letourneau's Husband Vili Faulaau Arrested for DUI

Mary Kay Letourneau's husband slammed into 2 vehicles stopped at a light, and when cops showed up they said he was drunk and high and busted him for DUI ... TMZ has learned.

Vili Fualaau was arrested on February 2, according to docs obtained by TMZ, moments after he failed to stop his Mercury Mountaineer in Burien, WA. Cops say he had a dazed expression, bloodshot eyes and slurred speech.

Vili agreed to take a field sobriety test, but just as he was about to start, cops say Mary Kay drove onto the scene and yelled at her husband to stop because their lawyer was on the way. Vili took her advice, and instead took a blood test at the station ... 2 hours later.

Prosecutors say his BAC was .08 -- the minimum level for DUI -- but he also had THC in his blood. Vili was booked for DUI, and posted bail. He's got a court hearing this week.

Interestingly, he's now 34 ... the same age Mary Kay was when she started having sex with Vili, who was in the 6th grade at the time.

TMZ broke the story, Vili filed for separation from Mary Kay last year, but later withdrew it.