A taskmaster, Mr. Ebeling pushed Mrs. Romney to excel in high-level amateur shows. He escorted her on horse-buying expeditions to Europe. She shares ownership of the Oldenburg mare he dreams of riding in the Olympic Games this summer. Mrs. Romney and her husband, Mitt, even floated a loan — $250,000 to $500,000, according to financial records — to Mr. Ebeling and his wife for the horse farm they run in California, where the Romneys stay in a Mediterranean-style guesthouse they use as a getaway…

It also offers a glimpse into the Romneys’ way of life, which they have generally shielded from view. Protective of their privacy, they may also have been wary of the kind of fallout that came after Mr. Romney’s mention of the “couple of Cadillacs” his wife owned and the disclosure of plans for a car elevator in the family’s $9 million beach house in California, which prompted criticism that Mr. Romney was out of touch with average Americans…

“Having people like that is very important to the success of this sport and our country being represented,” said Mary Phelps, the publisher of an online dressage news site, who estimated that the costs of exhibiting a horse on the international circuit could run to $200,000 a year.