Frederik reveals that he disowned both Basil, and Ralph before him, because they both reminded him of his own indiscretion when he himself had betrayed his wife during her illness because she could not be intimate with him.
Because they both reminded him of his own indiscretion when he himself had betrayed his wife during her illness because she could not be intimate with him. This was what he disowned both Basil, and Ralph before him. This is what Frederik reveals.