Squints from 'The Sandlot' -- Getting Divorced ... Not From Wendy Peffercorn

"The Sandlot" star Chauncey Leopardi's marriage has gone to the dogs -- just like that Babe Ruth baseball -- but turns out, it's been a long time coming, TMZ has learned.

Chauncey -- who played "Squints", the lucky kid who locked lips with Wendy Peffercorn -- married a woman named Stefani back in 2000. She filed for divorce last month.

But the couple hasn't been together for a while ... Stefani tells us they separated way back in 2003, they were just too lazy to file the docs ... until now. We're told the split was amicable.

The former lovers have one kid together -- a 10-year-old daughter. Stefani is asking for joint legal, but primary physical custody.

Speaking of physical -- remember this? Peffercorn ...