DEAR DEIDRE: I USED to be the envy of my friends with a girlfriend a decade younger than me, but since I’ve become a grandad, my fortunes have changed. We’ve gone from having a great sex life and relationship to the brink of splitting up within a few months. And now I’m worried she is getting too cosy with a work colleague.

I’m 49, she’s 38 and we met at a gym. I’ve always taken good care of my fitness and she was taken aback when I told her how old I was. Still, we fancied the pants off each other and when we got together 12 years ago she loved teasing me and calling me her sugar daddy.

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co.uk But when I became a grandparent she said it was a complete turn-off and now the intimacy has disappeared from our relationship. I love to cuddle and kiss my partner and be playful but now she withdraws when I touch her.

I have a grown-up son from a ­previous marriage and my partner and I have a six-year-old daughter between us. My son and his wife have recently had a beautiful baby girl. I’m so proud of her but my partner is embarrassed.

Around the same time that my granddaughter arrived, I saw photos on her phone where she was cosying up to a colleague. Something about her reaction to my.