Jennifer Lopez is "very happy" with Ben Affleck

An onlooker told PEOPLE: "They are having a beautiful trip.

"They celebrated Jen's birthday at a club last night. She looked gorgeous and very happy."

The couple - who had been set to wed back in 2003 but postponed their wedding due to "excessive media attention" before calling off their engagement the following year - have grown close again in recent months following Jennifer's split from Alex Rodriguez.

And, although the 52-year-old actress is "fully committed" to Ben, the brunette beauty isn't planning on jumping into marriage any time soon.

A source said recently: "[They] are fully committed to each other...

"They have been meshing their lives and families and don't feel the need to get engaged yet or even tie the knot.

"They have both been there and don't feel it's necessary. They are both very secure within their relationship and Ben worships her.

"It's truly meant to be and everyone around them thinks they are a perfect match."

But it doesn't look like it will be long before the loved-up pair take their relationship to the next level by moving in together.

An insider explained: "Their friends wouldn't be surprised if they move in together and ultimately end up together. They're spending all of their free time together and making each other a priority."

Ben has children Violet, 15, Seraphina, 12, and Samuel, nine, with his ex-wife Jennifer Garner, while J.Lo has 13-year-old twins Emme and Max with her ex-husband Marc Anthony, and their reunion doesn't seem to be "a big deal to either set of kids."