04/07/2008 at 01:00 AM EDT
On March 23, Drew Lachey and his wife of seven years, Lea, threw a backyard party for their daughter Isabella's second birthday. "Drew and Lea were great," says a close family source. "Their relationship is fine. Lea is a strong woman."
Good thing: Just five days earlier a tabloid report claimed Lachey had an affair with Cheryl Burke during a Dancing with the Stars tour last winter (Burke and Lachey were partners on the ABC show's spring 2006 season). Both Lachey, 31, and Burke, 23, strongly deny the allegation. "It's absolutely absurd," Burke told PEOPLE on March 24, after her quick step with actor Cristián de la Fuente on the show's new season. "It's been hard. My heart goes out to Lea and Isabella." Adds Lachey in a statement: "It's a shame that a tabloid is able to print such blatant lies about someone's personal life. These rumors are very hurtful to my family and me."
This is nothing new for Dancing cast members, whose chemistry with their partners (and some romances that really blossomed onset) fuels speculation. "I told Cheryl, 'You just have to not listen,'" says dancer Tony Dovolani, who shot down allegations of a romance with partner Sara Evans in 2006. Says Edyta Sliwinska, who's married to fellow pro Alec Mazo: "I wouldn't want Alec to think something will happen between me and my dance partner. [The gossip] puts all of the celebrities and dancers on edge."