Have Ryan Gosling and Eva Mendes split up? According to OK! magazine, the pair have hit a rough patch. A source told OK! that it is Gosling's inability to commit that has his girlfriend ready to call it quits:

"For the past 18 months, they've been talking about taking the next step, to the point that on every vacation, Eva's been convinced he would be popping the question. The trip to Iceland in September was the last straw. She pretty much gave him an ultimatum, but he balked and she stormed out and flew back to the States without him."

"Eva loves that man and wants to marry him-it's a shame she's not been able to convince him of that," added the source. And while the couple has "intense physical chemistry," the passion has begun to fade as more emotional issues are appearing.

"Ryan's commitment phobia is driving them apart, but there are other problems," says the insider. "They have vastly different family backgrounds and he's extremely introverted. He's never liked the fame game and has struggled with his heartthrob status. He'll choose an independent flick over a blockbuster, no matter how broke he is." But Eva, ofHitch fame, jumps at mainstream fare.

Meanwhile, rumor has it that the 'Lost River' director and his 'The Notebook' co-star and ex-girlfriend Rachel McAdams are back in tough.

"Rachel has been very low-key about it all," the source said to OK! Magazine. "She's played it very smart and used the whole 'just friends' angle to get close to Ryan again, but she 100 percent wants him back. He's not the cheating type, but he hasn't been honest with Eva about how much contact he has with Rachel."

In an interview with GQ soon after they broke up, Gosling said McAdams was one of the great loves of his life.

"I mean, God bless The Notebook," Gosling said to GQ. "It introduced me to one of the great loves of my life. But people do Rachel and me a disservice by assuming we were anything like the people in that movie. Rachel and my love story is a hell of a lot more romantic than that."