The 31-year-old former Neighbours actor, who is currently starring alongside Ventoura in Australian Outback drama Wild Boys, said that he once made a pact never to date someone else in the same industry.
MacPherson told the Herald Sun: "I vowed I would never date an actress after I was in my early 20s."
However, he did admit that dating Ventoura has plus points, saying: "Having a partner who understands the pressures of everything that goes along with being involved with the entertainment industry is very important. Because even my family don't quite comprehend what life is like."
The couple were initially coy about their relationship after being linked for the first time in August, but admitted that they are together on an episode of Rove McManus's US chatshow Rove LA last week.
MacPherson recently attended the Australian premiere of his first film The Cup, in which he plays late jockey Jason Oliver. However, he is flying to Los Angeles again this week.
"I've got a lot of good friends there and my little sister lives there," he said. "The goal is to work between here and there."