Slash -- Wife Says, Aloha ... I'm Leaving You

Slash's marriage is on the rocks -- TMZ has learned his wife has hightailed it out of L.A. and is already saying they're separated.

Sources close to the couple tell us Perla unexpectedly flew to Hawaii over the weekend with their 2 boys, and threw down a deadline of sorts -- telling Slash they need to work out their issues by New Year's or else.

It's unclear exactly what the issues are -- they've had plenty of blowups during 13 years of marriage -- but one source says ... "this time it's different." Although Perla is telling friends this a separation, we're told she hasn't filed legally.

We called Slash's reps -- they haven't gotten back to us -- but TMZ broke the story back in 2010, when Slash filed divorce docs ... only to withdraw the petition 2 months later.

We're told no one's mentioned the 'D' word this time around ... not yet. That could be especially messy since Perla is Slash's manager and runs all of his companies.

Welcome to the jungle.