Credit: Eric Charbonneau/

Marilyn Manson and Evan Rachel Wood are off-again.

What went wrong?

"They fought a lot," a source tells "It was always on and off. He's a creative mind so not the easiest person to be in a relationship with."

Manson, 41, and True Blood's Wood, 22, began dating in 2006.

They split two years later, only to reconcile a short time later before getting engaged this past January.