I’m in shock after catching a glimpse of my husband having sex with my mum

DEAR DEIDRE: THE worst thing imaginable has happened – I caught my husband having sex with my mum.

I still can’t believe what I saw.

I’m a woman of 31 and I have a little boy of five. My mother is 49.

I was the result of a one-night stand and I’ve never known who my father is.

For years it was just me and her. She had a few different boyfriends and nobody special until she met my stepfather when I was 15.

He’s lovely. He’s 55.

I’ve been with my husband for seven years. He’s 38.

We married four years ago and had such a ­fantastic wedding day I thought nothing would rock our world.

I’m a nurse so I often work nights and mum regularly helps with the childcare.

I had always felt so lucky that my mum and husband got on so well and never suspected a thing.

He had always been pretty flirty with her, but I just thought he was being silly to make her feel good. I didn’t mind a bit.

But thinking back she was often still at home, even after my husband had returned and there was no need.

One night, I began to feel feverish and started being sick so my manager insisted I go home.

When I went around the back of the house, through a crack in the curtains I saw my husband lying on top of my mother.