One person not happy about Selena Gomez and Justin Bieber getting back together? Her BFF, Taylor Swift.

A source told Life & Style (via Hollywood Life), “She [Taylor] just feels Selena is getting weighed down by the Justin drama.” It turns out, Sel's own mom agrees! ”Selena’s mom, Mandy, doesn’t want Selena held back by Justin,” the friend added. “She says he’s too much trouble.”

Gomez and Biebs were recently spotted on a romantic dinner date, but that's not enough to appease Sel's pals, because apparently Justin messed up big time. Rumors are growing louder that the cause of the split heard 'round the world was Bieber's wandering eye -- and that it wandered to his 'As Long as You Love Me' video co-star, Chanel Celaya.

“Selena was incredibly jealous between the amount of time they both were hanging out,” a source said. "And she was also jealous over the attention he gave to her. Selena then found texts that Justin sent to Chanel that were more sexually toned. Selena brought it up angrily to Justin who denied any wrong doing, which Selena then got more mad at Justin for lying ... making things that much worse.”

Yikes! If all that's true, we don't blame Taylor for feeling the way she does. Still, Jelena are giving it another go, but reportedly on Selena's terms. The 'Love You Like a Love Song' singer gave Biebs a few ultimatums before their reunion: No models or girls in his hotel rooms (more than fair enough), and they have to see one another at least once every two weeks.

Here's hoping the couple can work it out -- though if not, Sel and T-Swizzle may write a pretty awesome song about it.

Watch the Justin Bieber 'As Long as You Love Me' Video Feat. Big Sean