The TV and radio presenter told This Morning: "I've got two step-children. I was 29 when I met my husband it was quite an induction to being a proper parent. Rex adores and idolises them."
Jesse and Fearne, 33, married last year after the birth of their son, Rex, who turned two at the weekend. Jesse is the son of Rolling Stone Ronnie Wood.
When the couple started dating in 2012 Fearne had to adjust to being a step-parent to Jesse's children Arthur, 13, and Lola, nine, from his marriage to Tilly.
Fearne said she bonded with Jesse's kids and they're now a happy blended unit.
She also spoke about juggling her busy career as a Radio 1 presenter along with bringing up her young son, who turned two at the weekend.
She said: "My husband is away a lot, he's in a band, we have to be very militant, my cousin is our nanny, we are super organised.
"Any working mum takes a step back and thinks thoroughly about what choices they make, for me family comes first."
Fearne said: "I went round to see her with little Chester and he's so gorgeous and she's so happy.
"I would definitely love another baby. Being pregnant is the most incredible thing, even being in labour and giving birth. I loved all of it."