Brad's other crazy ex locked him in the cage while he was married to Tracy. She thought he had just ran off and left her.
Paul was the one who fooled around with Cassandra. He had been hired by her dying husband, who ended up framing Paul for his death, which was by his own hands for having an affair with his wife.
Then during or after the trial, Cassandra was the one who set her eyes on Brad. She drugged him to marry her.
She was killed by a hit and run driver soon after the marraige leaving Brad all of her money. That is why he does not need Vicky's money, Cassandras husband was richer than Victor.