The 37-year-old former husband of Jessica Simpson said that despite the romance of the occasion he was still worried about what her answer would be.
Appearing on Access Hollywood Live, Lachey said, 'We had a great evening, a great day, it just seemed like the right time.
'It was a romantic moment, a perfect moment, and she said, 'Yes', so that was the most important part.'
He added, 'I think that we have a great relationship. The good thing about our situation is that we kind of took our time with it. We've been together four and a half years, so it's just, the right thing at the right time for us.'