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.

Horrified, I was sick again outside, then went back to my car.

I got myself together, texted my husband and told him I’d be home in ten minutes. By the time I walked in the house, everything seemed normal, though my mother looked very red all down her face and neck.

I’m sure they were having sex. I just don’t know what to do.

DEIDRE SAYS:  What a terrible shock.

You’ve been betrayed by the two people you trusted most. If this was a one-off the chances are they both feel pretty awful.

Trust has to be earned and it will take time to get over this, if you ever can.

Get urgent counselling through Tavistock Relationships (020 7380 1975, tavistockrelationships.org) which prov­ides a quality service at a reasonable cost.

When you’re ready, tell your husband that he needs to come to the sessions too and the counsellor will be able to steer you through talking to your husband about what you saw.

My Cheating support pack has other tips to help you.

Pictures posed by models.