Complex sentence: During a conversation with Deacon about her love for Ridge even though she was married to Thorne, Brooke didn't know Thorne was listening and he dumped Brooke, who again immediately tried to get Ridge back.
Split into simpler sentences: During a conversation with Deacon about her love for Ridge even though she was married to Thorne, Brooke didn't know Thorne was listening. He then ended his relationship with Brooke, who again immediately tried to get Ridge back.