The former Hear'Say singer told Cosmopolitan that the couple, who have a daughter named Ava, have been too busy to wed.
Klass said: "I had every intention of getting married the next year but things happen.
"We know what's paramount and nothing would change if we got married. We will get married one day."
She added: "It was going to be the whole white wedding, the church bells, the whole thing but I think one day we'll be sitting in the Caribbean and someone will walk past and we'll say, 'Can you be a witness?'. It'll be spontaneous.
"As for the bridesmaids, obviously I'd have my little one, and I'd have Lauren Laverne. She's godmother to Ava and lives just down the road from me. She's brilliant."
Last October, Klass suggested that she had "gone off the idea" of marriage and was happy to "keep on living in sin".