And, for the 30-year-old, one of the biggest strains is the constant speculation about when she'll have a baby.
Although British sources say Kate wants to wait until 2013, after their Diamond Jubilee tour of the South Pacific, US magazines have repeatedly claimed she's already pregnant.
She faced further speculation in November when she politely refused some peanut paste - which pregnant women are advised to avoid - on a public engagement.
And last month toy company Arklu revealed it's been inundated with orders for a pregnant Kate doll.
‘People forget she's a normal person,' says Now's source.
‘She's also got the whole world discussing whether she's pregnant.
'OK, people are excited about a Royal baby, but they've got to think of the pressure they're putting on her.'
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