We can see why she's worried!

Hailey Baldwin and Justin Bieber have been photographed having tearful exchanges on multiple occasions in recent weeks, and now we're learning why things have been so emotional between the couple. It all has to do with the model's fear that Selena Gomez will always be The Biebs' true love!

"He tries reassuring her. But Hailey’s dealing with daily onslaughts from trolls online, plus his own mom and others in Justin’s circle who think Selena’s his soul mate, not her," a source dished to Radar.

The "Come & Get It" songstress also feels that JB is using his fiancee as his pawn to make her jealous.

"Selena’s friends all know that the only reason he got engaged to her was to get back at Selena. [Selena] thinks the whole thing is a joke and knows it will never last," the source added. Ouch!

It doesn't help things that the Guess stunner feels inferior to the brunette beauty.

“It’s very tough on her, because she’s quite insecure in her looks and thinks Selena’s so much more beautiful than she’ll ever be,” the insider revealed.

It's always hard to have the other woman lurking in the background waiting to pounce!