Complex sentence: At the beginning of season 9, Leonard and Penny proceeded as planned with their wedding and worked through their insecurities later, revealing they were both subconsciously trying to sabotage their relationship, each feeling unworthy of the other.
Split into simpler sentences: At the beginning of season 9, Leonard and Penny marry, although not without some initial problems. They both reveal that they were subconsciously trying to sabotage their relationship, feeling unworthy of the other.