Days before his wife Ashlee Simpson-Wentz filed for divorce, Pete Wentz made an appearance at the Hard Rock Hotel & Casino Punta Cana Grand Opening, but an ET source says the rocker was out of sorts.

With his curly hair in full effect, the Fall Out Boy bassist posed for photo ops, wearing a pair of jeans and a T-shirt that read: "I'm so happy I could just sh**."

Our source at the Dominican Republic hotel and casino said of Pete's disposition, "We thought [he] was just a moody rock star but it ended up being way more than an act. He stayed in his hotel room the whole time and never took the opportunity to talk to any fellow celebrities. He didn't even enjoy the beach!"

The couple released a statement to ET earlier today that reads: "After careful consideration, we have made the difficult decision to file for divorce. We remain friends and deeply committed and loving parents to our [two-year-old] son Bronx, whose happiness and well-being remains our number one priority. We ask that everyone honor our privacy as we navigate this next phase of our lives."

Pete, 31, and Ashlee, 26, were married in May 2008.

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