The 24-year-old singer – who has two children, Ruby, three, and 20-month-old Dexter, with her former fiance – first met her current boyfriend, songwriter Jonathan Powell, while she was still with Gavin but only realised she was attracted to him after they split in May.
She said: "I'd been writing with Johnny for a while, but it was a good couple of months after me and Gavin split. I asked Gav's permission in a way. I said to him, 'I really want you to know that nothing ever went on between me and Johnny while we were still together.'
"Johnny had a girlfriend when we were first working together, and I had Gav. And I'm not that type of person. I hadn't really noticed any feelings towards Johnny at that point. When I'm a taken woman, I'm a taken woman – that's the way I see things. And I've still got a lot of love and respect for Gav."
Although she has a new man, Charlotte still isn't fully over her separation from Gavin and has no intention of rushing her fledgling romance.
She said in an interview with heat magazine: "Johnny's amazing and brilliant, but it's early days and the split with Gav is still raw.
"He's really great, he's lovely – but to be honest, I'm pretty self-sufficient. It's all very early stages at the moment, but everyone is jumping the gun."
The 'Crazy Chick' hitmaker thought she would spend the rest of her life with 28-year-old Gavin until he returned from Norway earlier this year after filming Arctic wilderness survival show '71 Degrees North'.
She explained: "When he proposed, I was overjoyed. It was amazing. I really was going to marry Gav and spend the rest of my life with him. We had our problems as do any couple, but we just thought, 'We love each other and we'll get through that. We've got two beautiful children.'
"But then he came back from Norway and he'd changed and I'd had time to think and we were both like, 'What do you think?' We'd both had a change of heart. So we were both of the same mindset."