Ashlee Simpson & Pete Wentz's Post-Split Lunch

Ashlee Simpson and Pete Wentz are in the process of ending their marriage, but the former couple seem to be proving that their split is indeed amicable.

"They had lunch together today with Bronx at the Beverly Hills Hotel," a source told PEOPLE Monday, adding that Simpson is still staying at her parents' home in Encino, Calif.

Another source says the couple are not reconciling, but that their breakup remains friendly and being good parents to 2-year-old Bronx is their priority.

"They just had a meal together with their son," the source tells PEOPLE. "They're both focused on making this transition as easy as possible for him."

The couple – who pals say split because they wed too young, didn't have enough time to spend together and simply grew apart – announced last week that they were going separate ways.

Wentz, 31, and Simpson, 26, wed in 2008.

Credit: By Dahvi Shira and Pernilla Cedenheim for PEOPLE

Ashlee and Pete's Split: Early Signs of Trouble

Wedded bliss didn't last very long for Ashlee Simpson-Wentz and Pete Wentz.

Although the couple's Wednesday divorce announcement came as a shock to many, insiders saw trouble brewing way back in June 2009 -- when Ashlee, 26, and Pete, 31, were married for a mere 13 months, and prone to explosive blowouts often punctuated by alcohol.

At issue? Balancing their professional and romantic lives with the pressures of parenting an infant son, Bronx, then 7 months.

At the time, the duo fought "constantly," and singer-actress Ashlee was "seriously considering leaving him," one insider said.

Things boiled over at a June 1 party -- where a visibly drunk Ashlee got into a nasty public spat with Michelle Trachtenberg, Pete's ex girlfriend.

Simpson-Wentz was "reverting to drinking and going out, because she is sick and tired of her life," another pal said. The alcohol was "an outlet for her unhappiness, and Pete is getting fed up."

After hanging out in the same social circles for years, the couple got romantic in late 2006 -- and raced to the altar in May 2008, when she was 3-months pregnant.

"Ashlee loves Bronx but jumped into marriage and having a baby too quickly," one pal told Us. "They feel they got trapped in a situation they were too young for."

In Wednesday's statement released by their spokesperson, the couple said: "We remain friends and deeply committed and loving parents to our son Bronx, whose happiness and well-being remains our number one priority."

Credit: Us Magazine

Ashlee Simpson-Wentz Files for Divorce

The 2½-year marriage of Ashlee Simpson-Wentz and Pete Wentz is over, Ashlee's rep confirms to PEOPLE.

"After careful consideration, we have made the difficult decision to file for divorce," the couple said through a spokesperson. "We remain friends and deeply committed and loving parents to our son Bronx, whose happiness and well-being remains our No. 1 priority. We ask that everyone honor our privacy as we navigate this next phase of our lives."

According to TMZ, the divorce documents were filed in L.A. Superior Court, with Simpson, 26, citing "irreconcilable differences" and seeking spousal support.

In the court papers, which were signed by Simpson-Wentz on Monday and filed on Tuesday, it says the couple's date of separation is to be determined. Simpson-Wentz is seeking primary physical custody of their 2-year-old son, Bronx, with visitation for Wentz. She is also seeking to go back to her maiden name of Simpson and drop "Wentz."

Credit: Stephen M. Silverman for PEOPLE

Ashlee Simpson Shopping In West Hollywood

Ashlee Simpson-Wentz out doing some last minute Christmas shopping at Kidrobot, Wasteland and American Vintage in West Hollywood, CA on December 23, 2010.

Credit: Zimbio

Photos by Photo Agency

Ashlee Simpson: Ready to Celebrate Christmas

Tis the season for spending, and Ashlee Simpson was spotted boosting the SoCal economy on a shopping excursion yesterday (December 21).

The “Pieces of Me” songstress was joined by her son Bronx and mom Tina Simpson as she hit up a vintage clothing store in West Hollywood.

Credit: Celebrity Gossip

Ashlee Simpson & Pete Wentz Leaving Beso

Pete Wentz and Ashlee Simpson leave in good spirits after enjoying dinner at Beso in Hollywood last night, December 15, 2010.

Credit: Zimbio

Photos by PacificCoastNews.com

Ashlee Simpson's Awkward Family Xmas Photo

Ashlee Simpson and Pete Wentz broke out the ugly Christmas sweater, swept their hair back into the mullet of yore and shook their holiday printed pijama pants down to Third Street Promenade in Santa Monica, CA today (December 11).

Joined by their son Bronx Mowgli, the former celeb couple was all smiles as they pose for a family portrait onboard the Old Navy Awkward Holiday Photo Mobile.

Credit: Faded Youth Blog

Ashlee Simpson-Wentz's Son Doubling His Gifts

Kids born around the holidays sometimes feel short-changed in the gift department. But it sounds like Bronx Mowgli Wentz doesn't need to worry.

The son of Pete Wentz and Ashlee Simpson-Wentz turned 2 on Nov. 20, but Ashlee says he'll still have a nice Christmas – though they'll have to branch out in terms of presents.

"He just had his birthday, and he got a lot of gifts," the pop singer, 26, told PEOPLE on Monday at an Alice & Olivia toy drive in West Hollywood. "He'll still have a great Christmas, and he's really into Thomas the Train, but we have enough Thomas, so we do not need that this year!"

As Bronx gets older and more aware, his parents are beginning to develop family routines around the holidays. "For my husband and I, it's nice to start those traditions now," Ashlee says. "What we're doing with the tree, what we did over Thanksgiving ... we actually had an amazing Thanksgiving with Peter's family."

Looking to the future, those traditions will also include sister Jessica Simpson's future husband, Eric Johnson. Their relationship, says Ashlee, is as festive as anything this season.

"She is genuinely very, very happy, and you go to their house and it's warm and cozy, and it's a good feeling," she says. "And he's just a good guy."

And if Eric and Jessica happen to add to the family in the next few years, so much the better. "Of course it would be wonderful if it happened," says Ashlee. "We were actually over there yesterday, and Jessica is a wonderful godmother, and aunt, so I know she would be a wonderful mother."

Credit: People

Ashlee Simpson & Family Shop At Whole Foods

Ashlee Simpson, Pete Wentz and their son Bronx went grocery shopping at Whole Foods in Sherman Oaks today, November 24, 2010. The couple got into the holiday spirit and bought a poinsetta.

Credit: Zimbio

Photos by Photo Agency

Ashlee Psyched About Jessica's Engagement

How has Ashlee Simpson-Wentz been doing since hearing she'll be gaining a brother-in-law?

"Everything is so exciting!" Jessica Simpson's younger sister exclusively told E! News Tuesday when asked how she felt about big sis getting engaged to NFL alum Eric Johnson.

Well, that sounds about right.

Simpson-Wentz, who's been an old married lady for two-and-a-half years now, was also overheard gushing about son Bronx at the Solstice Sunglasses launch in Hollywood, telling a fellow guest, "He's getting so big!"

He sure is. Mom and dad Pete Wentz are already planning his second birthday party!

"It's going to be amazing," Ashlee told E! of the fiesta planned for this weekend at her parents' home in Encino.

Credit: E! Online

Jessica Simpson & Eric Johnson Are Engaged!

Jessica Simpson is off the market!

Sources confirm to Us Magazine that the singer, 30, became engaged to beau Eric Johnson on Thursday, just days after Us broke the news that her ex-husband, Nick Lachey, popped the question to Vanessa Minnillo, his love of nearly five years. Simpson and Lachey, 37, split in 2005, after three years of marriage.

On Saturday, Simpson flashed a sizable ring on her left hand during an appearance at Dillard's at Oak Park Mall in Kansas City.

The Texas native began dating the former NFL player in May while he was estranged from his first wife, stylist Keri Johnson; their divorce was finalized five months later.

Though Ashlee Simpson-Wentz recently told Us that her sister "is happy, so we're all really happy," sources insist that most of Simpson's friends are concerned about Johnson's motives for dating the singer.

"Eric was never that successful in the NFL, but he's always wanted the celebrity lifestyle," a source told Us in October. "Her friends do not trust him."

Credit: Us Magazine

Ashlee Simpson: Shopping With The Family

Ashlee Simpson-Wentz, Pete Wentz and their son Bronx out shopping at Tough Cookies Children's Boutique in Sherman Oaks, CA. Ashlee was showing off her new short hair-do.

Credit: Zimbio

Photos by Photo Agency

Ashlee Simpson: Decades of Denim Dame

She’s always up for a good time, and last night (November 2) Ashlee Simpson was spotted at the Decades of Denim Launch Party.

The “Pieces of Me” songstress looked super sexy as she arrived at the Los Angeles shindig, sporting a sleeveless black sequined dress with black heels.

Credit: Celebrity Gossip

Ash Simpson & Pete Wentz: 'Runaway' Premiere

Looking for a little Monday night action, Ashlee Simpson and Pete Wentz were spotted at the premiere of Kanye West’s short film “Runaway” in Los Angeles.

The “Pieces of Me” songstress and her “Sugar We’re Going Down” rocker hubby both looked to be in good moods as they arrived at The Harmony Theatre on Sunset Boulevard.

Credit: Celebrity Gossip

Platinum-Blonde Ashlee Simpson: LAX Airport

Showing off a brand new blonde hairdo, Ashlee Simpson was spotted jetting out of LAX Airport in Los Angeles, California on Tuesday (October 12).

The former "Melrose Place" star was all smiles as she proudly debuted the platinum blonde pixie cut while toting her adorable boy Bronx in her arms.

Credit: Celebrity Gossip

Ashlee, Pete & Bronx: Sherman Oaks Playdate

Bringing an end to the weekend with a family excursion, Ashlee Simpson and Pete Wentz took Bronx Mowgli out to a local park in Sherman Oaks, CA on Sunday (September 26).

The "Melrose Place" cutie and her Fall Out Boy hubby eased their way to the kiddie's paradise as they watched on while their young son played in the sand in between utilizing the swingset and slides.

Credit: Celebrity Gossip