We thought they were in it for the long haul!

Danny DeVito and Rhea Perlman have separated, his rep confirms to Us Weekly.

The couple, who wed in 1982, have three children together: Lucy, 29, Grace, 27, and Jacob, 25.

The longtime pair seemingly had one of the strongest marriages in Hollywood, so this comes as quite the shock to many. Once asked what the secret to a happy union was, the Cheers alum summed it up simply, saying, "Love. I mean, really. [But] you know what? Who knows. The secret to success is to try to never figure that out."

The cause for separation has yet to be revealed.

Sad!

I can't think of anything else Danny DeVito has been in except Batman Returns. Oh, and any movie with Michael Douglas!

The 5-foot-tall actor posed for some pix outside of Madeo in Beverly Hills Sunday night. Did you know he was once considered for the role of George Costanza on Seinfeld? Random!

We spotted Danny DeVito trying to hail a cab in New York yesterday - emphasis on trying! Maybe the driver didn't see him all the way down there?