Around one in five British adults admit to having cheated on a partner, according to research by YouGov. Coworkers are one of the most common choices for affairs, cited by 38 percent of unfaithful individuals. Anna*, 48, is one of them. She has been married to Dave* for 16 years, but for 12 of them, she has been having an affair with Mike*, whom she met at work. Here, she explains how she’s managed to live a double life for so long, and why she has no plans to leave her husband.

If you saw me out with my husband, you would think we’re pretty happily married. Despite being married for 16 years, we are still incredibly affectionate, make each other laugh and have great sex, but I also harbour a dirty secret. I have been having an affair with a former work colleague for almost 13 years and have no intention of stopping.

It all started with a drunken kiss in a quiet corner of our office Christmas party in 2013. There was an instant attraction between Mike and I when we’d started working together that summer. We flirted in that way married people sometimes convince themselves is harmless, and joked about being each other’s work spouse. It felt almost inevitable something would happen between us.