“That’s at the top of my list of questions I have for them both.” Had I seen any signs? Since we’d moved to London, Matt had worked late a lot. But we’d come down from Manchester because he was offered his dream job. Of course he was going to put body and soul into it.

When had he had time for an affair?

We were at the stage where I bought Matt’s underpants and he reminded me that I’d not called my brother for three weeks.

We were a team.

We were in love.

We were going to spend the rest of our lives together.

Or so I’d thought.

I should be crying, but for some reason the tears hadn’t arrived. Perhaps I didn’t believe it was true. Perhaps the fizzle of anger I was beginning to feel had dried them out.

Karen had been a part of my life since the day we’d both started school. I always felt slightly unkempt next to her. Even then. At five, her knee-high white socks never fell down, wrinkling at the ankles like mine did. At thirteen she never suffered with acne and wrestled with cover-up, and in our twenties, I’d never seen her with a single clump of mascara or eyeliner that was smudged.

Karen had known Matt since before we were a couple. She’d come up to visit me in Manchester, during our first term at university, twirling in, making the boys drool and swapping make-up tips with the girls in my block. She’d been struggling to fit in at Exeter, which made no sense to me. All my friends loved her.

When Matt pulled me onto the dance floor during the summer ball, told me I brought out the best in him, and he liked my boobs, I was thrilled Karen had already met him so she could help me overanalyze every part of our relationship.

Seven years later, Karen knew Matt almost as well as I did.

“Maybe you should go to the wedding and when they do that bit about impediments, you can stand up and ask that question,” Florence suggested. “But obviously, you can’t go.”

“Of course, I can’t go,” I replied. Despite the invitation, I was almost certainly the last person Karen wanted at her wedding. It wasn’t as if seeing my ex-boyfriend—the man I’d thought I was going to spend the rest of my life with—marrying my ex-best friend was top of my list of things to do this summer.

“Are you going to go?” I loved Florence like a sister, and if Karen was capable of sleeping with my boyfriend, what could she do to Florence?

“Of course not,” she replied.