The 33-year-old reality star and her businessman beau have been spending plenty of quality time together
, and a source close to the couple tells ET the two are "having a good time."
"Christina and Doug are both homebodies," the source says of their similar sensibilities. "They like to hang out, BBQ and watch movies. They've enjoyed spa days, bike rides, nice dinners and sunset boat rides together."
Their relationship has also progressed to the point that Christina's two children with estranged husband Tarek El Moussa -- 6-year-old Taylor and 1-year-old Brayden -- have met Doug's six children.
"All the children get along really well and they have fun hanging out," our source notes.
Christina and Doug spent the Fourth of July together in Newport, California, where they were snapped cuddling
on her luxury boat. Our source says their children were also involved in the festivities.
"They spent the morning with all the kids at the pool, and then the day on Christina’s boat, tubing with the kids in the ocean," the source says of how the couple spent the holiday. "During the evening they watched fireworks and lit their own sparklers."
Meanwhile, Tarek spent the Fourth of July in Lake Havasu City, Arizona, clearly enjoying himself while flyboarding.
"When I'm not with kids being a dad, which is my favorite thing, I love traveling and staying active!!" he later Instagrammed alongside a photo of himself in Arizona. "I've been very blessed to be surrounded by amazing people and amazing friends. I'd say I'm a pretty lucky guy!!!"
Last month, a source told ET that Christina and Doug have actually known one another for 10 years
, and that the Flip or Flop
star dated him before her relationship with Tarek.
Watch the video below for more on Christina and Doug's romance.
-- Reporting by Brendon Geoffrion