But Kelsey, 34, has been plagued by vicious online trolls who won't accept the fact that she has found love again.
In her first-ever joint TV interview with new partner Will Lindsay, Kelsey said: "It's been three years... this is Tom's three-year anniversary of his death and it's almost like people want me to feel guilty for moving on."
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Kelsey was devastated when Tom lost his battle with brain cancer aged just 33, four years after they tied the knot.
She met tree surgeon Will, from Kent, on a night out last year.
The pair announced their romance in September and podcaster Kelsey, who is due in June, says her third pregnancy was a "happy accident".
She and Will appear together on STV's Lorraine today as part of its March4March mental health initiative.
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On the show, Kelsey, who is mum to Aurelia, five, and Bodhi, four, with Tom, asks Will: "Does it stress you out that I get upset about trolls and people commenting on our relationship?"
Will replies: "Not really, I just tell you not to look at them, don't I. There's bound to be some people sending nice messages, but block out the haters."
Kelsey said: "I'm always going to have guilt, but what's so hard is that Tom's not here any more so what do people want me to do?
"Our house was full of so much sadness but now it's full of happiness, the kids deserve that more than anything. They've been through so much. I feel like we are taking the steps forward to heal but I just want other women to feel like it's OK to move on.
"It's not taking anything away from the love I had for Tom."
Kelsey, who also runs a performing arts school, speaks about the positive impact meeting Will has had on her life.
She said: "I do feel like you're the best thing that's happened to me since losing Tom.
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You're so understanding. Our first conversation was about you losing your dad. You've been through the same thing as the children.
"You have an understanding of loss. If people haven't gone through loss they will never understand it. Walk in my shoes, then understand how I feel."
Will says meeting Kelsey was the "best thing that ever happened" to him.
He tells her: "Just to see how strong you are as well and how strong you have been through it all - like you say, you've had to be because of the kids.' Getting emotional, he continues: "Straight away, it's been amazing since I met you. I knew I definitely wanted to spend more time with you...