The couple, who met on The Bachelor, now have two daughters together, and Snez also has her daughter Eve from a previous relationship.
Proud dad Sam, who also announced that today marks Willow's second birthday, said their new baby girl means he's outnumbered even further - but he's not too bothered by it.
"We're going okay - they're keeping me in touch with my feminine side," Sam said.
"The girls have come to absolutely love Charlie, and from day one they thought she was gorgeous," Snezana said.
"Willow is very motherly - she loves trying to help out with changing nappies and during feeding time, and Eve's been helping out when I have to bathe one of them."
Snez also gave an insight into her fitness journey since she became a mum for the third time.
This time around, she's also taking part in Sam's eight-week challenge.
"I've just started working out again and I took it really easy this time," Snezana said.
"Every baby is different and every pregnancy is different, so you've got to go at your own pace - we're not in any hurry, but I'll be there to help her," Sam said.