At 3:17 in the morning the police rang to tell me my husband had been killed in a crash, while he was asleep beside me with one leg over mine. The officer said: leave the room without waking the man next to you.

And the smart lock on our apartment had no record of Cassian leaving. None. According to that system he was inside from six in the evening.

When I put the phone down I remembered two more things.

He had made me a hot milk before bed and stood there while I took my tablet for the insomnia, which he has never once done.

And when I woke up at 3:17 he was in grey pyjamas, and I would have sworn in a courtroom that he went to bed in the black ones.

He left for work at half eight.

I opened the lock app.

There are three fingerprints on that door.

Mine. Cassian’s. And a third one with no name on it, added eight months ago.

It has come through my front door forty-seven times.