JENNIE GARTH’s second post-divorce romance has gone up in flames because the former “Bev­erly Hills 90210” actress can’t get over her messy split from actor Peter Facinelli, say sources.

The 41-year-old blonde’s ro­mance with big-bucks media exec Michael Shimbo collapsed after a heated argument while the pair were at a Grand Prix race in Austin, Texas, on Nov. 17.

A friend said it was Shimbo who decided to end things, believing Garth hasn’t got­ten past her divorce, which ended amid rumors of Fa­cinelli’s infidelity. The pair – who have three daughters, Luca, 16, Lola, 10, and Fiona, 7 – had separated in 2012 and their divorce was finalized in June.

Michael lives in San Fran­cisco while Jennie lives in L.A., so the time they spent together was very precious to him,” said the friend. “But when they were together, he had to listen to Jen­nie harp about what a jerk she thought Peter was being, how things are tough for their girls and how her life was just turned upside down by her divorce.

“In Texas, Michael finally asked her, ‘Why can’t you get past this?’ and suggested she put some distance between her and Peter. Jennie got red-faced and said, ‘He’s the father of my children, and I can’t just shut off being a mom!’

 “At that point, Michael told her it’s for the best if they just parted ways because she obviously still has issues she needs to work out.”

Another friend adds Garth’s continual bumping-of-heads with “Twilight Saga” star Facinelli, 40, also doomed her romance with her former boyfriend, rock musician Jeremy Salken, who told a friend that Garth “only seemed half into the relationship.”

As The ENQUIRER reported last month, Garth lashed out at Faci­nelli over his public displays of affection with his gorgeous ac­tress girlfriend Jaimie Alexander, 29, and was incensed when they moved into a new home in Toluca Lake, Calif., on the same street where he and Garth raised their daughters during their 11-year mar­riage.

Still, it’s not always a “War of the Roses” with those two.

Garth was seen on Nov. 3 playing happy family while dropping off Fa­cinelli at LAX with their daughters in tow.

“That’s what stuck in Michael’s craw,” said the friend.

“Jennie would gripe about Peter one day and then spend time with him the next. There is clearly something more going on, something that Michael didn’t want to be caught up in.”