Complex sentence: She accuses him of being unable to no longer be "on top" in the relationship and confronts him over how his deception nearly ended her own career, then becomes mortified when she realises that was his intent.
Split into simpler sentences: She accuses him of being unable to cope with no longer be "on top" in the relationship and confronts him over how his deception nearly ended her own career. Then, she becomes mortified when she realises that was his intent.