The 44-year-old, who has been with her backing dancer beau for almost two years, has not been pictured with Smart, 26, in more than three weeks.
‘Jennifer is pretty private about the relationship, but she’s been hinting that the spark is gone,’ a source close to Lopez says.
‘She’s having a hard time ignoring the fact her head has been telling her for a while that this thing with Casper isn’t forever. And now her heart’s saying the same thing.
‘They’re obviously in very different places in their lives, and Jennifer wants to take responsibility for her life and not repeat the same mistakes she has made in the past.’
According to Radar Online’s insider: ‘She enjoyed the relationship for what it is, but now that giddiness has turned to sadness.’
Lopez recently admitted she is hard to please when it comes to her relationships.
‘I have my own high standards for what I want in a partner and how I want to be treated,’ she said. ‘I bring a lot to the table.’