Khloé, who has not been seen in public with Lamar since 2 June, was spotted leaving a gym in the Woodland Hills area of Los Angeles on Thursday without her rings, despite having worn them at previous work-out sessions.
The 29-year-old star has also updated her Twitter profile picture to one of herself, posing on top of two cars, and removed the previous snap of her and her basketball player husband.
Khloé and her husband have brushed off rumours that Lamar had cheated on her with Jennifer Richardson, after meeting the brunette in Washington D.C last year. Their affair allegedly ended in March 2013.
Since then, another woman, lawyer Polina Polonsky has also claimed that she had a six-week romance with the basketball star.
Despite rumours of a rift, Khloé and Lamar are said to be renewing their vows to mark their wedding anniversary this September.
"It's difficult for Khloé that people are questioning her marriage, but she's strong and Lamar is her world," a source told People.
Earlier this month Khloé mother's Kris Jenner slammed reports that the couple were preparing to call time on their four-year marriage, calling the rumours "ridiculous".
"Khloé and Lamar are absolutely not getting divorced," the Kardashian matriarch stated. "There's been no talk of divorce."
Kris then went on to say that both Khloé and Lamar were at her house two days ago, and that everything was fine. Lamar, however, was not present at a family dinner held a few weeks ago to celebrate the 16th birthday of Khloé's half-sister, Kylie Jenner.
The couple took steps to show they were more in love than ever when the rumours first came out, posting romantic snaps on Instagram. Sources close to the pair have also insisted that they are not going to split, and that Khloé has not contacted a divorce lawyer.
"Part of being married is knowing when your husband needs your support," Khloé said in the past. "I'm a modern girl, but you should put your husband first. I like to think divorce is not an option."