Someone who knew him well once told me that, right before testifying, he was told they could go easy on him if he allowed some VIPs to meet his wife. That sent him over the edge with contempt for the hearings and redefined his persona. Hard to be a real socialist living in a CT estate, though. Wait a minute, I take that back. That's really easy.
He didn't marry Monroe until after his appearance before HUAC, and he had just divorced his first wife a few months before.