The on-again, off-again couple were first spotted walking into church in Beverly Hills on Wednesday, before enjoying an intimate dinner date later on in the evening.
Gomez kept it casual, stepping out in patent leather flats, and a plaid blazer, while Bieber sported a denim jacket, khaki pants and checkered tennis shoes.
An eyewitness tells ET that Gomez left a New York City residence around noon on Wednesday and flew back to Los Angeles.
"Selena made it back in L.A. in time to spend Valentine’s Day with Justin," says the eyewitness. "They went to church and then went to the Montage for dinner. They were at church around 8:30 p.m. and stayed for about an hour."
The couple were seen getting out of separate cars at church but did head to dinner in the same vehicle. The eyewitness says the two hung out at the eatery until about 11 p.m.
"She'll be doing this [going to therapy] periodically as a check-in," the source noted. "It's really to stay ahead of anything and to ensure she continues to be healthy, and that's something Justin supports 100 percent."
As ET previously reported, the 25-year-old "Wolves" singer voluntarily checked herself into a wellness program in upstate New York earlier this year.
"Justin was one of the first people she saw when she got out of rehab," the source added. "He was very supportive of her taking care of her health. In the past, it was always Selena pushing Justin to take care of himself, like by introducing him to Hillsong [Church]. Now, it's his turn to push her to take care of herself."
"They've both matured and have very different priorities. Justin isn't interested in partying and Selena is much more confident, and isn't afraid to put her needs ahead of anyone else's," said the source. "They've done the fame thing for so long, now they just want to work on quality projects and live a low-key life."