Robert Pattinson to Kristen Stewart -- I Dumped Our Mansion ... Like I Dumped Your Cheating Ass

Robert Pattinson has just gotten rid of the L.A.-area mansion he once shared with Kristen Stewart ... ya know, before she cheated on him with the married director of that "Snow White" movie.

We've learned ... Pattinson just closed the sale of his 4,026 square foot Spanish Colonial home in Los Feliz for a cool $6.35 MILLION.

The "Twilight" star has only owned the home for a few years -- he bought it back in Sept. 2011 for $6.275 ... so not a huge profit, but better than taking a loss.

The mansion is pretty incredible -- with a great back yard, 3.5 bathrooms and a steller master bedroom that Kristen Stewart probably never saw again after July 2012 ... when she went behind Robert's back and hooked up with the very married Rupert Sanders.