The actor, who previously played Edie's husband in Desperate Housewives, had signed up to star in new ABC series Scoundrels.
However, Deadline Hollywood claims that McDonough was replaced by David James Ellicot after just three days when he said that he would not film intimate scenes because of his Catholic faith.
ABC is allegedly angry that McDonough was unaware of the scenes as he had been sent the script weeks prior to filming. Meanwhile, one source claimed that he even refused to kiss his co-star Virginia Madsen.
"It wasn't just 'heated love scenes'," the insider explained. "He wouldn't do any kissing whatsoever, even though those scenes were clearly in the scripts he read before taking the role. He didn't tell the producers that cast him on this show that he had any issues with this until shooting started. So unprofessional, and such a shame because he is a great talent."
Another source said: "It has cost him jobs, but the man is sticking to his principles."
ABC cited cast changes for McDonough's replacement and refused to reveal details of why he had left the show. A spokesperson for McDonough refused to comment.