DEAR DEIDRE: I HAD sex with my daughter’s partner after a heavy night out with colleagues.

I feel so ashamed of myself now.

2 I feel so ashamed of myself after having drunken sex with my daughter's boyfriend Credit: Getty - Contributor

I’m 48 and a widow. My husband died in an accident at work not long after my daughter was born.

She’s 24 and met her partner at university. They have been an item ever since. He’s 27.

They’ve both got good jobs in London and rent a flat together.

I work for a large charity and was invited to be one of the table hosts at a fundraising dinner in London recently. My daughter suggested I stay over with her and her partner.

2 The sex was more trouble than it was worth Credit: Getty - Contributor

I don’t go out often so the alcohol quickly went to my head and I was pretty drunk by the time I got into the taxi to go back to my daughter’s place.

She was out at a friend’s 30th and her partner was at home with their son, who is nearly a year old.

We had a couple of drinks together and talked about a lot of things, then I moved in towards him to kiss him but he declined.

I remember thinking how attractive he was. He’s a good-looking, tall guy who keeps fit.

I said: “I think I’d better go to bed.” He said: “Yes, that may be a good idea. I’ll take your bag upstairs.” He had to help me after I tripped on the first step.

We got into the spare room and he took my shoes off for me. I fell back on the bed.

Next thing I remember, he was kissing my neck, my clothes were off and we had sex.

I feel so guilty. I didn’t know what I was doing. What was I thinking?

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I tried to be normal with my daughter the next day but keep going over the whole thing in my mind.

I’m wondering whether he has cheated on her with anyone else, as he was quick enough to do it with her mum.

But I really don’t want to tell my daughter. The consequences would be severe. Should I just forget all about it and move on?

DEIDRE SAYS: If your daughter gets to hear about this, then you stand to lose your otherwise good relationship with her and perhaps contact with your grandson too.

You behaved foolishly but you’re not solely to blame – this was a terrible act of betrayal by you both.

Find a moment to talk to your daughter’s partner, and tell him this was a stupid mistake on both your parts and you want to ensure your daughter never finds out.

Be alert to signs of him cheating with anyone else or your daughter feeling distressed. And when you’re out, take care to keep your drinking down to a reasonable level so you can stay in control.

Alternating soft drinks with alcoholic ones will help.

This may have happened partly because your own social life doesn’t include enough opportunity to meet a possible partner of your own.

You can find understanding and social contact through the charity WAY (widowedandyoung.org.uk).