It has been a summer of discontent for Robert Pattinson. Since his longtime girlfriend and “Twilight” co-star Kristen Stewart was photographed in intimate poses with another man a few weeks ago, the heat on his life has been daunting.How does he deal with it?”“It drives you nuts,” he says of all the hoopla.“It’s just nuts.“I don’t know how I cope with it. I really don’t know,” he says in a good-…