Blake Shelton admits being a stepfather has changed him "in every possible way"

He told Entertainment Tonight: "I learned quickly, not because anything happened, but just, you know, reading the room, you've really got [to think], 'I have to take a step back'.

"When people say it's not about you anymore when you have a kid... I think, if you're doing it right, it's not about you anymore. That's true."

Blake first met the 54-year-old No Doubt singer a decade ago when she joined 'The Voice', and while they didn't talk much during that first season, eventually "the pieces were falling together".

He is looking forward to the future, and he admitted he'd be delighted with "a repeat these past 10 years".

He said: "If I could have a repeat of these past 10 years, [that] would be perfect.

"Next month, we've got an 18-year-old, which it blows my mind that already happened. And in a couple of years, we'll have another 18-year old.

"And that's... it's gonna be I guess a lot more alone time, which I'm not mad about that either. But we still have Apollo, so we have another almost 10 years before we can kick him out, so it should be a lot of fun."

When it comes to the way he has embraced raising Gwen's children and taking them in as his own, Blake has been inspired by the way his father treated his younger brother by marriage.

He previously told the Country Radio Seminar: "He took Richie on and raised him from the time he was 1 year old, and my brother never thought of my dad as anything other than his dad.

"The example that my dad set for me was that [child] was not even a consideration [in a romantic partnership]. You got three boys? Awesome! My dad did it.

"My dad raised me. I could do this. I didn't know what I was signing up for, but I was all about signing up for it. And every day I've fallen in love with the boys as much as I do with Gwen."