For a time Monty dated cast member Phyllis Thaxter but his real passion was for an actor and the pair were inseparable until he went into the Navy in 1942. His life would prove to be one of sexual confusion. Predominantly gay, he also had affairs with women and Bosworth would later claim - rather simplistically - that it was his inability to deal with his sexuality that helped turn him to drink and drugs.

In 1942 he appeared in the experimental play Mexican Mural. It was a significant moment in Monty's life for it was then that he met Mira Rostava, Kevin McCarthy and Libby Holman (pictured below as a young woman). McCarthy and his wife Augusta became close friends, vacationing together and providing Monty with a surrogate family. McCarthy described him as a remarkable person and was flattered by his interest in them. Rostova was a Russian and would later become Monty's acting coach, accompanying him on the set of most of his early films. Her presence - nodding approval or disapproval to particular scenes - usually enraged his directors. Holman, however, was the most intriguing of the three. A former torch singer and bisexual, she had married the heir to a tobacco fortune who was later found dead of gunshot wounds. She was charged with his murder but acquitted and, after a legal battle, inherited his money. She was old enough to be Monty's mother and, perhaps because of that, they became very close. Some suggested their relationship was sexual, others denied it but few would argue that she dominated him in much the same way as his mother. Monty's relationship with his real mother Sunny had, by now, become truly love-hate. He seemed dependent on her yet resented that dependence at the same time and in 1943 he found himself a home of his own where he could escape at weekends.

His 1944 appearance in Lillian Hellman's play The Searching Wind, another drama with a war theme, made him Broadway's top young actor and for a time he considered making the film version for Warners. Instead, he continued on the stage. His last role would be in the Tennesee Williams-Donald Windham work You Touched Me!

Monty had always said that he wanted to be the greatest actor in the world and Hollywood had for many years been trying to sign up that talent but he seemed in two minds. He knew it would bring him stardom and great wealth but he was rightly wary of the studio system, with its seven-year contracts and their stipulation that an actor appear in roles and movies determined by the studio bosses. Monty refused to have anything to do with them - he only wanted great roles with good scripts and respected directors.

He got his break in 1946 when Howard Hawks cast him as Matt Garth in his western Red River - the story of how the Chisholm Trail was developed as a cattle drive. There were no long-term contracts to confuse the issue. Monty played opposite John Wayne as the great star's adopted son but they didn't get on. In the story Monty has to rebel against Wayne's despotic rule. The pair end up in a bloody fight and Monty was worried about his ability to carry off such a macho scene. The film was not released until 1948 but on its opening Monty earned great acclaim - the first of many such notices during his career.