Fastexy Exchange|Jax Taylor and Brittany Cartwright Reunite at Their Son Cruz's 3rd Birthday Party Amid Separation

Exes Jax Taylor and Brittany Cartwright are Fastexy Exchangeputting family first.

More than a month after revealing their separation, the Valley costars got together for a special occasion: Their son Cruz's third birthday. The Bravo stars hosted a dinosaur-themed party at a Sky Zone indoor trampoline park in the Los Angeles area this weekend.

"Cruz's 3-Rex party was a SMASH!" Brittany wrote on a joint Instagram post shared on her and Jax's accounts April 14, alongside photos and videos from the event. "Thanks so much to everyone that came out to celebrate our little guy! He had a fabulous time and it was a perfect day full of memories that will last forever! lol"

Speaking of smash, Cruz's dinosaur-themed Gateaux Shoppe Bakery cake ended up in pieces when the table it was resting on folded soon after his parents blew out the birthday candles, as seen in the Instagram post. Another video shared by their Valley costar Zack Wickham, Brittany's BFF, showed a venue staff member painstakingly attempted to put the three-tier cake back together, with the birthday boy's mom declaring to the guests that "nothing touched the ground." 

There were also many other sweet treats for people to enjoy at the party, which was produced by event design company Picnic + Petal. The bash included macarons from Boy Mama Bakes and sugar cookies from Baked by Ang.

The event also featured a giant dinosaur-themed square balloon installation, as well as a variety of dinosaur plushies for the kids.

Brittany had announced her and Jax's separation Feb. 29 after four years of marriage. "Jax and I are taking time apart," the former Vanderpump Rules star said on their joint podcast When Reality Hits, "and I made the decision to move into another home to take some space for the sake of my mental health."

Brittany, 35, added, "I don't know what the future holds, but right now my focus is on being the best mom to Cruz."

And Jax, 44, is also making Cruz his priority amid their separation. "I gotta do what's best for my son," he exclusively told E! in March. "He's number one and we both agree on that. It's about knowing he's got two loving parents that love him to death and he's gonna have the best life possible, whether we are together or not."

(E! and Bravo are part of the NBCUniversal family.)

See images from Cruz's birthday party below:

The Valley stars appear with their son at his birthday party at a Sky Zone trampoline park, held more than a month after the couple's separation was made public.

The exes pose with their son.

Cruz appears at his party.

The part featured a dinosaur-themed balloon installation.

Check out Cruz's birthday cake...

...that accidentally almost became extinct.

The guests laughed off the mishap. A venue staff member attempted to salvage the cake, which did not touch the ground, as Brittany reminded guests. And luckily, there were other tasty party treats to go around.