Synthesized answer
The author provides evidence that Richard Curwen fell "wildly, passionately" in love with Antonia, who returned his affections [1]. However, both Richard and Antonia were penniless and unwilling to live ordinary lives, desiring "the best" [1]. To achieve this, Richard married Eloise, Antonia's wealthy but frail cousin [1]. The passage notes an astonishing resemblance between Eloise and Antonia, to the point where "most people couldn’t tell them apart" [1]. The author explicitly states that Richard was "counting on" this resemblance [1].
The provided passages establish the circumstances leading to Richard's marriage to Eloise and his motivations based on the resemblance between the cousins and his desire for wealth. However, the passages do not provide further evidence of his actions after the marriage or any specific details beyond this initial setup.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: Bride of Moat House by Norah Lofts Description: It began when he met Antonia. Richard Curwen fell in love—wildly, passionately—and the lovely Antonia returned his love. But Richard and Antonia were penniless. And too spoiled and selfish to live as ordinary mortals. They wanted the best. The very best. And so Richard married Eloise, Antonia’s frail but wealthy cousin. The resemblance between Eloise and Antonia was astonishing. In fact, most people couldn’t tell them apart. Which was exactly what Richard was counting on.