From PEOPLE Magazine Click to enlarge
Jennifer Lopez isn't one for subtlety: The natural-born performer loves to flaunt what she's got, including her men. So it was that nearly one year after Lopez performed a wildly sexy dance on American Idol alongside her husband, Marc Anthony, she did so again, this time scorching the stage with her new love, 25-year-old dancer Casper Smart. "They had so much chemistry between them," says an audience member who attended the pre-taping for the May 10 show. "It was sexy." In between takes, "they were smiling at each other the whole time," says another observer. "They were like a high school couple."

And they said it wouldn't last-more than a few weeks, anyway. Yet as they hit the six-month mark of their unlikely romance, Lopez, 42, and her backup-dancer boyfriend (she's referred to him as "Bear" on Twitter) are going strong, even as they continue to break all the rules in the Serious Relationship Handbook: 1. Beware a 17-year age gap. 2. Don't rush things. (Smart moved into Lopez's Hidden Hills, Calif., mansion at the start of the year.) 3. Avoid casting your boyfriend as your love interest in a white-hot video that takes PDA to a whole new level. (See "Dance Again," the same song they brought to life on Idol.) Casting Smart in the video "was her idea," says director Paul Hunter. "They had a good, fun vibe going on." It's a vibe Lopez is eagerly embracing these days. "I just feel really in the zone," she said at a May 5 press conference for her new romantic comedy What to Expect When You're Expecting. "I feel good about everything."

But not everyone is so enthusiastic. Given that Lopez started dating Smart just four months after her split from Anthony, 43 (with whom she has 4-year-old twins Max and Emme), a Lopez family source says some members of her inner circle "worry that Casper will take advantage of her. She has fallen so hard."

She doesn't seem to fall any other way. "I'm a bit of a romantic, if you hadn't noticed," she recently said with a laugh. But for someone who's been famously unlucky in love, the thrice-wed Lopez seems almost defiant toward the naysayers. Describing "Dance Again" as "where I'm at," she sings, "Nobody knows what I'm feeling inside/ I find it so stupid/ So why should I hide/ That I love to make love to you baby ... Only got just one life this I've learned/ Who cares what they're gonna say?"

What people close to the couple are saying is this: Smart is "super friendly," but he also can be "immature" and "cocky," according to one source. Meanwhile, Lopez's longtime manager Benny Medina said in the April issue of Vogue that he would prefer that his love-'em-and-marry-'em client-who wed Anthony just five months after her split from ex-fiance Ben Affleck-would take things more slowly. "The thing that I sort of always wished is that she would give herself time to just naturally meet someone, instead of having nearly obsessive guys pursue her," Medina said. When she started dating Smart, "she was like, 'It's not even the age, Benny. It's actually that I just came out of a relationship where I felt like I was kind of not getting what I needed. And I'm open!'"

Enter the laid-back, fun-loving dancer, an Anaheim, Calif., native who "makes her feel young," says the family source. (They met months before they began mixing business with pleasure.) "After she split with Marc, Jennifer was concerned that no one would want to date a 42-year-old mom. She was upset and she felt old and tired. With Casper, she's come alive again." His magic? A Smart family friend says the dancer "has a great sense of humor," while another source notes, "He treats her like a queen." (He even picked confetti out of her hair at the end of her Idol performance.)

Whether at play with the kids in Hawaii or at work, Smart-a fixture on the American Idol set who will help choreograph Lopez's summer tour-showers the singer with the kind of attention she craves, says a music-industry source. "She thrives on having a one-on-one relationship where she feels special," says the source. "Casper centers everything on Jennifer. He watches her, praises her and makes her feel like she is the only woman in the room. It is like he apprenticed from Marc and learned what it takes to get to her. You can see that she loves it."

She also loves Smart's easy manner with her kids. "They often have dance parties at home with Max and Emme," says the family source. "Casper is like a big kid and is not afraid to act goofy. He is a fantastic extra dad for them."

Anthony, who filed for divorce in April, has come to accept Lopez's new relationship. "He has moved on," says a source close to the salsa star. And while they're still hashing out a custody schedule, Lopez's attorney Ron Anteau told PEOPLE the pair "are working together to reach a friendly resolution." Indeed, they are set to perform together on the May 26 live airing of their show ¡Q'Viva! The Chosen. Anthony, Lopez said in January, "is always going to be in my life."

But with Smart, the spotlight-stealing star doesn't struggle with the fights and jealousy that plagued the final months of her marriage. "They have an easy relationship," says a source. "Casper is a very go-with-the-flow type of guy." At the same time, the source adds, Smart isn't just a lazy hanger-on. "He is ambitious and works hard."

Will the wedding-loving star say yes to the dress for a fourth time? Her rep shot down wedding rumors in March, but "no one would be shocked if she decides to marry him," says the source. She is also open to expanding her family. "It would be a blessing," she said recently. Adds a music-industry source: "If she could get pregnant with Casper, it would be a happy day for her."

  • Contributors:
  • Reported by Pernilla Cedenheim/Los Angeles,
  • Melody Chiu/Los Angeles,
  • Vanessa Diaz/Los Angeles,
  • Patrick Gomez/Los Angeles,
  • Marisa Laudadio/Los Angeles,
  • Dahvi Shira/Los Angeles,
  • Liz McNeil/New York City,
  • Linda Marx/Miami.