The handsome actor, who popped the question to Jen in 2012, has revealed that he and his fiancée are in no rush to walk down the aisle.
" There is this hum of pressure that – I can't stress enough – I don't pay any attention to," Justin, 43, told Australia's TV Weekly.
"But I am not going to let a tabloid tell me what to do… I'm not going to watch them tap their watch….
"We're just doing our own thing. We are completely happy, obviously, but we're not on anyone else's timeframe."
Justin added that his life has been "enriched" since finding love with Jennifer, 45. "I find love in anyone's life creates expansion. And needless to say, it feels really good," he said. "So it's only enriched by life."
Alongside planning a wedding, Justin is focusing on his career – which, by his own admission, still surprises him.
"My career has followed no particular path," said the actor, who has also written a number of Hollywood hits including Tropic Thunder, Rock of Ages and Iron Man 2.
"As I'm sure you're aware, I have the dumbest career in the world as far as 'Yeah, I'll do that'. I've really guided myself on what is going to be the next fun thing to do, I don't think of it in terms of, 'Will this be smart for my career?'"
Justin is currently starring in HBO drama The Leftovers. He appears in the lead role as police chief Kevin Garvey Jr in the series, which takes place three years after a global rapture, known as the 'Sudden Departure', which caused the inexplicable disappearance of 140 million people, two per cent of the world's population.
He spoke about relating to the show's themes of grief and loss.
"I've lost good friends, I've lost family members," Justin said. "Then there's the obvious comparison, although I'm reluctant to compare a TV show to September 11.
"That event was, as a New Yorker, the first and hopefully last time I'll feel that sort of collective grief. It made a big city feel incredibly small."