Henry detailed falling for French after watching her perform at a comedy club in his forthcoming memoir, Rising to the Surface, which will be published on 30 August.
French and Henry tied the knot in 1984 and remained married for more than 25 years, before announcing their separation in 2010.
Prior to meeting French, Henry said he had been “serial dating”, but none of these relationships were based on companionship.
“Most of them were fuelled purely by physical attraction. Besides, I lacked attention span when it came to actually being with someone,” Henry wrote in an extract of the book, published in The Sunday Times.
“So, I found myself growing lonelier by the minute. I was yearning for something more substantial, but I just didn’t know what that was.”
The Lenny Henry Show star said it was refreshing to have a “reciprocal conversation with someone and not have to perform or amuse them”, and that French, a fellow comedian, could make him laugh.
“A massive light bulb went off over my head. I was compelled by [Dawn]. We talked about everything… performance, politics (my family voted Labour, but I hadn’t really connected with the whys of it until I met Dawn), family, relationships, food, the future.“
“Even at the worst of times we used humour as sword and shield. My mind was at last tuned in, focused and functioning as an equal in a relationship. In other words, I was in love.”
The couple married at St Paul’s Church in Covent Garden, London in October 1984.
Henry said they wanted to have “as big a wedding” as they could, to show friends and family that they “meant business”.
“To my mind, if we weren’t going to get married in the right way — big church, reception, dress suits, food, friends and family jammed into a fancy-schmancy chi-chi hall with a big band and Big Al the DJ winding up the day’s events with a big disco — then we might as well not do it at all,” he said.
Henry and French’s relationship has remained amicable following their split, with French telling The Mirror in 2017 that they are the “best of friends”.
“Remarkably, we seem to have shifted with relative ease from a 25-year marriage to a lasting friendship. I am amazed by us.
“There is no war, we’ve turned out to be the best of friends. There were lots of good years but one tricky last year.”