According to reports, the pair are just so busy buying houses, being pregnant and whatnot they'd rather wait until after the baby is born before walking down the aisle.
"They have a lot going on right now," and insider told E! Online. "They've been focusing on prepping for the baby and the new house."
The news comes as Mila and Ashton coughed up a cool $10million for a 7,000-square-foot-mansion in Beverly Hills to call their own.
While speculation was rife for months, Mila only recently confirmed her pregnancy on the Ellen DeGeneres Show. She told the host she's a pretty run of the mill preggo lady and craving gherkins and ice cream.
"He assumed that I was gonna have goofy cravings, so he stocked our secondary fridge with weird food.
"Just like pickles, and sauerkraut, or like anchovies, and ice creams... Just in case at one point during this pregnancy I'd be like I really want something."
Before you ask, yes, you did just read the words "secondary fridge".
LOVE MILA? See more from the expectant star in the gallery below.