Sally Field claimed that her ex Burt Reynolds let envy get the best of him as her star was on the rise, detailing how he was “not happy” with her career buzz ahead of the 1980 Academy Awards. The Forrest Gump star recalled the strained connection they had at the time in Dave Karger’s new book 50 Oscar Nights, in which stars and filmmakers discuss their Academy Award wins and share never-before-told tales from over the years. “He really was not a nice guy around me then,” she shared, RadarOnline.com has learned. At the time, Field had become the talk of Hollywood for her performance in Norma Ra…