Jennifer Lopez and Casper Smart's families are both hoping the on-again, off-again couple not only survive this time around, but can one day soon find their way to the altar.

A source told Radar Online, "All of their relatives on both sides are hoping this time really works for them because their families would be thrilled if they got married one day."

Word is the 46-year-old Lopez has already met Smart's mother and grandmother, and he long ago became a favorite of the twin children she shares with former husband Marc Anthony.

Meanwhile, reports are swirling that the lovebirds plan to spend the upcoming Thanksgiving holiday vacationing in Mexico. 

All the recent bliss aside, if history is any indication, the smart money might lay in not expecting the couple to be exchanging their "I Dos" anytime soon.

"Since they got back together earlier this year, he's probably proposed at least five times," a source said. "Frankly, she's sick and tired of saying no. Every time he pops the question, it bugs the hell out of her. She finally snapped and told him to stop asking, but he won't."

"She loves Casper -- she just doesn't want to marry him," a source added. "She's told him it's never going to happen. Period."

The 2011 People Magazine "Most Beautiful Person" award winner and the 28-year-old Smart were first romantically linked late that same year. The three-time married "Jenny From The Block" singer has also dated celebrities like Ben Affleck, Sean Combs, Wesley Snipes and Tommy Mottola.

The next several months figure to be a busy time for Lopez. She is set to star in the NBC police drama "Shades of Blue" and serve as a judge, alongside Harry Connick, Jr. and Keith Urban, on the final season of the long-running "American Idol."