The Southpaw actor, 34, spoke about relationships on Howard Stern's Sirius XM radio show Wednesday, revealing how many times he's been in love, and why it never worked out in the end.
"How many times in your life have you really been in love – really in love?" Stern asked.
"Three times," Gyllenhaal replied, before hedging a bit and adding: "Twice."
He didn't name names – the actor has dated a number of stars, including Kirsten Dunst, Reese Witherspoon, Taylor Swift and Alyssa Miller – but placed the blame on himself for relationships failing even when he was in love.
"It was me, man," he said. "I think I probably just got scared."
Gyllenhaal added that he's not in love at the moment, and he admitted he's a little sad about that. "I love love, man," he said. "Are you kidding me?"
So, will he ever get married?
"Oh, I hope so," Gyllenhaal said. "I think it's hard for everybody, man. But I also think at some point, you just decide to grow up, you know?"
He added: "There are a lot of beautiful women, and there are opportunities. But at the same time, if you find the right person ... I believe in monogamy. I believe in when you meet somebody who's right, it will be right, and you'll stay there."
"I admire that relationship. They're definitely a standard for me," Gyllenhaal said. "To me, making a relationship ... where you're like, 'Oh, I'm psyched to be a dad. This is cool. I'm psyched to be in this.' My sister and her husband make it feel that way."