LeAnn Rimes was reportedly "sobbing hysterically" at the prospect of her husband cheating on her.
The singer is married to Eddie Cibrian. The pair began their relationship while Eddie was stilled married to Brandi Glanville and LeAnn was wed to Dean Sheremet.
The couple subsequently divorced their spouses and tied the knot in 2011.
LeAnn's representatives announced that she is seeking treatment to address "anxiety and stress".
Infidelity has been on LeAnn's mind for quite some time.
"LeAnn called a friend of hers a few weeks ago sobbing hysterically about Eddie going out," a source told Radar Online.
"She was home for the weekend and he didn't stay in with her and she was crying saying that she was so worried about what he was doing when he wasn't with her.
"LeAnn is beyond stressed about the cracks in her relationship with Eddie and she has been really scared that he is cheating on her."
LeAnn has apparently been experiencing an emotional meltdown for months.
Teacher Kimberly Smiley recalls an expletive laden phone call she received from the musician weeks ago.
"[LeAnn said] 'Hey b**ch this is LeAnn you have 5 minutes to say whatever you want to me!' " Kimberly recalled to the website.
"I even asked her to watch it, saying, 'Your language -- so trashy!' I was also surprised that she thought I'd just change my mind about her and want to come hang with her. I don't like her, not because of the affair (although I don't agree with it), but because of her taunting of Brandi and using [Eddie's children] in her sick game."
© Cover Media