Sean Penn to Esquire: Charlize Theron would be real 'first marriage'

LOS ANGELES, Jan. 29 (UPI) -- Sean Penn is amazed by his relationship with girlfriend Charlize Theron.

The 54-year-old actor opened up about the 39-year-old actress in an interview with Esquire magazine. Penn was married to Madonna from 1985 to 1989 and Robin Wright from 1996 to 2010, but told the publication he would consider Theron his first marriage.

"Yes, I'd get married again," he said. "You say I've been married twice before, but I've been married under circumstances where I was less informed than I am today, so I wouldn't even consider it a third marriage, I'd consider it a first marriage on its own terms if I got married again."

Penn spoke of his passionate, deep and true connection with Theron, and declared it "romantic and a lot more fulfilling" to be with someone who makes him feel like a good person. He also said he and the actress possess "a shared ethic" he didn't have with former partners.

"Yeah, I'm surprised to be in love," he said. "I'm self-proclaimed bad at mathematics, but I can do two plus two: 53 years old plus finally beginning to figure out why you haven't been happy in a single relationship? It could seem too late."

Penn and Theron have been together since January 2014, and confirmed their relationship in May. News the actor will adopt Theron's 3-year-old son, Jackson, broke last week amid rumors the couple are secretly engaged.

Penn recently directed Theron and Javier Bardem in romantic drama The Last Face. He and Bardem will co-star in an adaptation of Jean-Patrick Manchette's novel The Gunman, and the actor will receive an honorary Cesar award in February.