Complex sentence: It seems that Mr. Bellamy and his son did not approve of the liaison between Maud and McPherson; indeed, they do not even find out about the engagement until this meeting, as such had been the secrecy of their affair.
Split into simpler sentences: It seems that they did not approve of the liaison between Maud and McPherson. They do not even find out about the engagement until this meeting, such has been the secrecy of their affair.