Hayden Panettiere haydenovermilo.jpg

Is this because he's looking angry 24/7? Or maybe just the huge age gap?

A week and half ago we reported that Hayden Panettiere was getting sexy with Jesse McCartney (I know, right?), and now Us reports that the Heroes hottie has split with boyfriend Milo Ventimiglia... coincidence?

A source close to the couple says: "It was a lifestyle conflict. They were in very different places. They are still on friendly terms." The insider then adds that Hayden "is young. She likes to go out in the Hollywood scene and that's not his style."

Tell me about it!