Ryan and Eva – who have eight-month-old daughter Esmeralda together – are reportedly embroiled in a battle over how to split their fortunes if they ever called it quits on their relationship.
A source told US’ OK! magazine: “It’s just business, but it’s a real tug-of-war – she has more money than he does.
“Ryan just wants 50/50 all the way, end of story, but it’s not as simple as that.”
Friends of the pair – who have been dating since 2011 – believe Ryan is using the prenup as a delaying tactic to avoid tying the knot with the 41-year-old beauty.
Meanwhile, an insider previously claimed that the pair have never felt marriage is a “huge priority” for them.
They said: “Neither felt the need to get married, it’s just not a huge priority for either of them. They know what they have.
“Ryan and Eva are super-super-private. The last thing they’d do is bring a baby … to a film set teeming with paparazzi. Ryan specifically wanted it like this – with paps following him in Atlanta, they’re mostly leaving Eva and the baby alone.”