Pass the Tissue! The Heartbreaking Reason Kristin Cavallari & Mark Estes Split

Kristin Cavallari is "newly single." 

After the news broke during Alex Cooper's "Unwell" tour live show in Austin, Texas, an insider spilled the heartbreaking reason for her split from Mark Estes. 

"As they started to get more serious in their relationship, issues started to surface. They kept having conversations about the future but weren’t aligned," the source told US Weekly. 

The insider dished that the two "were on different pages" regarding their future. 

Estes reportedly was ready to "settle down and start a family," however, The Hills alum, who shares kids Camden, 11, Jaxon, 9, and Saylor, 8, with ex-husband Jay Cutler, was "very content with her life and family" at the moment.

READ MORE: Kristin Cavallari Reveals ‘Hottest’ Guy She Ever Hooked Up With (Spoiler: It’s a Fellow Reality TV Star!)

Their 13-year age gap also played a part in their breakup, as Estes was ready for something stable, and Cavallari, 37, enjoyed being "independent."

"Having another baby was something Kristin wasn’t sure she was on the same page about. Them being in different stages of life was the dealbreaker" the source stated. 

READ MORE: Kristin Cavallari Became Very Underweight During Her ‘Really Unhappy Marriage’

Despite parting ways, the former flames are on good terms.

Kristin really liked Mark and enjoyed their time together, and there’s no animosity between them. They genuinely had a lot of fun but it ran its course. She is excited to focus on herself, her businesses and her kids right now," the insider added.

The Uncommon James founder began dating the 24-year-old influencer in February.