I seduced my girlfriend’s sexy younger cousin, but now she says she’s in love with me and threatening to tell all

DEAR DEIDRE: MY girlfriend’s sexy younger cousin promised me a night of no-strings fun. But now she’s threatening to drop me in it unless I step up. I’ve been dating my girlfriend for 18 months. She’s 28, I’m 32. We have a lot of fun but we’re not exclusive — she’s hoping to emigrate later this year, so we’re keeping it casual. I have feelings for her and see her about four times a week. Her cousin is 23 and STUNNING. They’re close-knit so I often see her at family BBQs and parties. I get the impression that the cousin looks up to my girlfriend and wants to be friends, but my girlfriend just seems to find her annoying. She’s usually bubbly and outgoing. When we all went to the races together at Easter, however, she’d just been dumped and seemed withdrawn. Live Chat and Contact Dear Deidre Live Chat with one of our trained counsellors Monday to Thursday from 1pm to 4pm. In Live Chat Hours:On your desktop or mobile, a ‘live chat with us’ button will appear below. Click it, and the chat box will appear and you will be connected with one of Deidre’s team. If you’re on the The Sun app, click here. If you would like to contact any of the counsellors outside of these hours, you can contact us:Via email: deardeidre@the-sun.co.ukOr send a confidential form here.DM us on Instagram: @Dear DeidreDM us on Facebook: @DearDeidreOfficial I spent the day trying to cheer her up and afterwards we stayed in touch through messaging. Kidding myself I was helping her, I kept texting her compliments. Eventually she suggested a quick drink. I told my girlfriend I was seeing the lads, but I spent the evening crammed into a bar booth with this sexy girl. Things heated up and we ended up back at my place, having sex all over my flat. Physically she was amazing but she’s a bit superficial and not as genuine as my girlfriend. During and after sex she was clingy and emotional. She cried at one point, telling me she felt like she was falling in love. I backed off afterwards, scared of leading her on. But she won’t let go. She messages and calls me several times every day, hounding me to see her again. When I politely explained it was a one-off, she hinted that my girlfriend might like to know I’ve been sleeping with her cousin. She says she’ll tell all unless I start treating her properly. I don’t think my girlfriend would talk to me again if she ever found out. What should I do? DEIDRE SAYS: You were kidding yourself. You weren’t genuinely trying to help this younger woman. Instead, you used her for a night of non-committal fun with no intention of seeing her again. While your relationship with your girlfriend might not be exclusive, I’m sure there’s an unspoken agreement that extended families should be out of bounds. With the younger cousin threatening to tell all, you have a tough choice to make. You can keep it a secret and hope that she won’t reveal the truth — but that will keep you at the mercy of her emotions which, as you’ve seen, are running high. Or you can tell your girlfriend yourself and face her reaction. She might understand that you were giving in to a moment’s temptation. But she might also be angry that you took advantage of her younger cousin. Even though she might not like her cousin’s personality, I’m sure your girlfriend still cares about her. Your girlfriend also won’t appreciate that you lied to her. Unless you want this hanging over you until your girlfriend leaves the country, you’ll have to tell the truth. You might find it ends this relationship, but you’ll have learned a lot about non-monogamy. When relationships are non-monogamous, trust is paramount. If you constantly find yourself avoiding intimacy, you might benefit from understanding where that fear comes from. My free support pack How Counselling Can Help has more information. Dear Deidre’s Open Relationship Ordeals From experimental flings to emotional fallouts, open relationships regularly appear in Deidre’s inbox. One man found group‑sex encounters with his girlfriend he met through an open‑relationship app left him embarrassed and unable to rise to the occasion. Another reader admitted that what started as an agreed open relationship with her boyfriend quickly turned tense as the balance of attention shifted and jealousy flared. And a third woman’s open marriage fling backfired when it became public, leaving her estranged from family. OPEN RELATIONSHIPS BY NUMBERS Research from YouGov found that 1 in 25 Britons say they have been in a consensual non-monogamous arrangement at some point and a further 1 in 14 say they would be open to exploring it. A UK survey by OnePoll revealed that around one in six Brits would consider a non-monogamous relationship if it were more socially accepted. Men are three times more likely to consider a non-monogamous relationship (23 per cent) than women (8 per cent). In London, according to a survey commissioned by Rayden Solicitors, as many as 27 per cent of residents believe monogamy is no longer “realistic” in modern relationships.