Marcus Grodd and Lacy Faddoul seemed to be head-over-heels in love on the "Bachelor" spinoff, "Bachelor in Paradise." The two hit it off pretty early on and were inseparable the entire time. The ABC dating show ended with Grodd proposing to Faddoul on the beach, but a new report claims the couple has hit a bump in the road.

According to In Touch magazine, Grodd (who competed on Andi Dorfman's season of "The Bachelorette") cheated on his fiancée with another reality star. Grodd and Faddoul got engaged at the end of June but had to keep their happy news a secret until the show's finale aired in September. During the few months the two kept their engagement hidden, Grodd and Faddoul didn't get to see each other that much.

A source told In Touch that while Faddoul was in her hometown of San Diego secretly planning her wedding, Grodd was in Dallas dating Jessie James Decker's little sister, Sydney Rae James. James stars on the E! show "Eric & Jessie: Game on."

"They went on a date and kissed," the source told In Touch, adding that Grodd kept his engagement hidden from James.

"Sydney thought his romance with Lacy was over," the source claims. "He was all over her. Meanwhile, poor Lacy has been planning their wedding this whole time. If she knew about Sydney, she'd flip."

A few days ago, Grodd and Faddoul did an interview with ABC affiliate WFAA and said that the time apart wasn't easy.  

"It was difficult," Faddoul said. "We sent cards back and forth and he sent me lots of bridal magazines and we saw each other every two weeks until now."

Grodd said the hardest part for him was keeping the engagement a secret.

"It's a little hard keeping it a secret but I guess ABC taught me real well and I kept a good poker face," he said.

As far as the wedding, the couple was mum on the details but said they are still planning and trying to figure everything out.