"There are a lot of beautiful women and there are opportunities," he acknowledged, "but... I believe in monogamy. I believe in, when you meet somebody who's right, it'll be right and you'll stay there."
Gyllenhaal, 34, told Stern that he's been in love two or three times in the past, but he's not in love now. He blames himself for those relationships not turning into more serious unions.
"I think I probably got scared," he admitted. "But I also think at some point, I think you just decide to grow up."
"They're definitely a standard for me... based on their kids and how great they are with their kids," he said.