Justin Timberlake & Jessica Biel Try to Hold it Together

Despite the rumors buzzing around Justin Timberlake and Jessica Biel, the couple seem determined to make things work recently, appearing in public holding hands and going on romantic vacations. But sources tell OK! it'll take a lot more than hand holding to get through their relationship problems.

“Justin and Jessica bicker constantly,”  the insider tells OK!. “You sometimes feel like you’re watching an older brother with his younger sister.”

So what's making them fight in the first place?

Justin has been publicly accused of having a wandering eye — which is said to ignite a jealous streak in Jessica — but the insider says the twosome has been fighting over smaller issues for months.

“Usually he complains about her dogs, her career choices and even the TV shows she watches,” says the source.

While the Easy Virtue actress is happy to kick back in sweats and no makeup, Justin is “a perfectionist, to the point that he irons his T-shirts. Sometimes he follows behind Jessica’s two dogs wiping the floor wherever they leave paw prints!”

Guess we'll have to wait and see whether or not Jessica's puppy love will get in the way of her relationship!