Steven Tyler and Erin Brady, his fiance of one year and girlfriend of five, have officially split up. Surprisingly, it had nothing to do with his penchant for dressing like a '70s era Stevie Nicks -- and everything to do with how he treated her.

A source near the couple confirmed, "It's over for good this time."

Rumors started swirling about the duo when Brady was noticeably absent from Tyler's New Year's Eve celebrations with his family in Hawaii. It was particularly noteworthy considering it was the same locale where Tyler proposed to Brady and also where the couple had a commitment ceremony in 2011.

(Apparently "commitment ceremonies" are all the rage among straight celebrity couples right now, either because they're not ready to get married or because they can't since, you know, they're already married to other people.)

Despite claims that the relationship fell apart because Brady pushed Tyler off the sobriety wagon, a source says the real reason for the split was rooted in how he treated her.

"Steven was just not that nice to her in the end. His family and entourage never really accepted her and she can do better," the insider said. "They're still friendly but they're going their own ways. The engagement is off."

Next up for Tyler: his newest tour with Aerosmith, where he will continue to cover himself in feathers and scarves and refuse to acknowledge that he's a 64-year-old man.