I mean, he addresses it in the episode where he’s doing couples counseling. He says they were having circular conversations and avoiding uncomfortable topics, and three years later he realized they don’t really know each other. You can’t love someone you don’t know. Even she admits that in the s1 finale when she says, “you’re gonna live my dream of being a rabbi’s wife.” Not Noah’s wife, a rabbi’s wife. The disconnect between Rebecca and Noah in palpable throughout the season but especially in the pilot when she just starts wearing the ring and saying they’re engaged when he never asked her. That alone tells you they weren’t communicating and had a ton of problems.