Jessica Simpson made a very public show of togetherness with Tony Romo at sister Ashlee's "Alice in Wonderland"-themed weekend knot-tying with Pete Wentz, but it did little to quell rampant rumors that their six-month-old romance is on the rocks. Further fueling talk of trouble: Us says the unlucky-in-love blonde, 27, was sans her quarterback beau when she jetted off to Cabo San Lucas, Mexico, on Sunday with her parents.

Jessica and Tony exit New York's Waverly Inn in March.

The Texas twosome's appearance at the wedding regrettably took some of the focus off the bride, who is believed to be about four months along with a Fall Out Boy-spawned bundle of joy.

"Jessica did not look happy the entire night," a guest tattles to E! News. "She just wasn't her bubbly self. She was very subdued and she and Tony barely interacted the entire night, except for some dancing at the end."

The body language-reading spy then concludes, "You could tell she was really happy for her sister, but that maybe she was a little bit sad that things aren't working out as well for her."

But did Jess, who served as maid-of-honor, turn her toast to the newlyweds back around to her own romantic status? E! says during her "emotional, off-the-cuff" tribute, she mentioned how Ashlee and Pete's matrimonial felicity "has inspired me to love again."

Meanwhile, the Chicago Sun-Times says Romo "looked a little uncomfortable" while making small talk with Jessica's dad-manager-string-puller Joe Simpson, who Us claims "begged" the Dallas Cowboys star to come to the nuptials "to support the family."

By the by, Papa Simpson performed the ceremony and is said to have turned on the waterworks several times, which apparently wasn't a commentary on his new son-in-law. According to E! News, the former minister described Wentz as "a very patient guy." (Amen to that.)

A far sunnier picture of Jessica and Tony's wedding day date is painted by People (incidentally, TMZ says the magazine is coughing up "well over" a million bucks for the vow-swap exclusive).

The mag says all was sweetness and light for the rumor-plagued pair, who stepped out Friday for a paparazzi-covered lunch at a Los Angeles sushi joint and were together that night for the rehearsal dinner -- hosted by Simpson at her Beverly Hills pad.

"They were very cozy and cute together," enthuses a pointedly positive mole. "They were kissing and holding hands throughout the night. He was very sweet to her. They were very much a couple."

The People source also dismisses Us' cover story claim that Simpson is still pining for her Jennifer Aniston-wooing ex, John Mayer, scoffing, "She's definitely not mourning John Mayer! She was in an amazing mood and so happy her sister was getting married."

The Sun-Times snitch concurs, saying, "You would never know that anything bad was going on between them. He looked great, she looked beautiful and they were smiling and laughing for most of the night."

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