The Affair will return for a second season, airing 10 new episodes in 2015. It averages 3.9 million viewers per week.
Homeland, meanwhile, will enter its fifth season with 12 new episodes. It averages 6 million viewers weekly.
"In its fourth season, Homeland has brilliantly reinvented itself. It continues to capture the attention of a devoted fan base, and has provided an enviable platform for the successful launch of The Affair," said David Nevins, Showtime president. "With thought-provoking, relevant and addictive storylines, both series have been embraced, dissected and much debated week after week. We’re excited to see more from these complex shows in 2015."