Hayden PanettiereHayden Panettiere has finally revealed the reason for her split from boyfriend of a year Stephen Colletti last September.

The Heroes actress, who is now dating co-star Milo Ventimiglia, told Seventeen magazine that being in a serious relationship was too much to deal with at the same time as her career was exploding: “I just knew I wanted to breathe. I wanted to be single at the time.”

“It just hit me like a ton of bricks - this is the time I need to be with myself.”

She added that she’s also not the easiest of girlfriends at the best of times anyway: “It takes such a secure person to be with someone like me; it takes so much confidence, it takes so much trust.”