Sean Penn Romancing Natalie Portman?

The quesionably reliable STAR Magazine is reporting that Sean Penn and Natalie Portman are having an affair and this is what prompted his divorce papers to be filed. According to STAR:

Weeks after Star broke the news that Sean Penn was seen making out with Natalie Portman, the Oscar winner filed for separation from his wife Robin Wright Penn. Now Star has learned that Sean, 48, and Natalie, 27, are still seeing each other!

"She stimulates him in ways no other person has, mentally or professionally," says a source. "There's a lot more there with Natalie than any of the other girls Sean's been with."

It was Sean's indiscretion with Natalie that encouraged Robin, 43, to stop turning a blind eye to his philandering. "She was furious he was messing around with such a young star," says an insider.

As Star reported, Sean and Natalie were seen in a passionate embrace following dinner — during which they were "constantly touching each other" — at Sunset Tower Hotel's Tower Bar on March 17.

"They went to a bank of elevators that only goes to the spa or to private rooms," an eyewitness told Star at the time. "They came back about 45 minutes later, and that's when I saw them making out."

I hate to see Sean and Robin's marriage end - but it never seemed like the healthiest of relationships, did it? All the breaking up and making up. Very passionate, I'm sure. Given their track record, I won't be surprised if they get back together.

Adultery/cheating aside....what do you think about Natalie Portman and Sean Penn as a couple?!