The entertainment reporter, 33, gushed to Us Weekly exclusively about the engagement and her future husband, with whom she already shares one son Charlie, 2 months.
"He is the love of my life and I love him and my family so much," McLarty tells Us. "I feel like the luckiest girl in the world!"
The actor, 42, popped the question at Mastro's Ocean Club in Malibu, presenting the brunette beauty with a gorgeous ring from Roseark, McLarty's favorite jewelry store in Los Angeles. "David got a beautiful black and white diamond dome ring for her," Roseark's Rick and Kathy Rose tell Us. "He has amazing taste and style and wanted to get her something that was different. Of course he would choose a ring like this."
The proposal was a family affair, as the Scream 4 star popped the question in front of Charlie and Coco, his 10-year-old daughter with ex-wife Courteney Cox.
"He asked her with Coco and Charlie at a family dinner because he wanted the kids to be there and all of them to be together," a source tells Us. "She was in the restroom at dinner and when she came out, he told her Charlie had been screaming and crying in the restaurant and asked her and Coco to come calm him down outside, and that's when he asked her to marry him."
The insider tells Us Weekly exclusively, "He flew to Las Vegas to ask Christina's dad Bud McLarty for permission a while ago, so it's been in the works."
The couple's anniversary is the Fourth of July, which inspired the timing of the engagement, the source adds. Arquette and McLarty first met on an '80s-themed boat party on a past Fourth of July.
Arquette and McLarty's engagement comes just one week after Cox said "yes" when her love Johnny McDaid proposed. The timing is purely coincidence, however, the insider tells Us Weekly, adding, "It has nothing to do with Courteney's engagement."