Q. I’ve started seeing a guy and I’m really happy, but my ex-boyfriend has just arrived in London. I still have feelings for him – what should I do?

Ruby says: You should welcome the return of your old flame. Our entire society is founded on principles of competition and your new man should be under no illusions – he either brings his A-game or you leave him hanging.

Some people will tell you this is unfair or manipulative but it’s nature’s way – men competing to have sex with females ultimately benefits the entire species, because it prevents the weaklings and defects from breeding. It’s why peacocks have feathers.

In my experience, we can never truly escape our sexual histories – and I don’t just mean because of STDs. If I had a dollar for every sexless marriage I’ve abandoned for a toxic chancer from my past, I would have ten dollars.

Give each of these guys three nights and alternate Sundays.

Dear Reuben

Reuben says: Sometimes we under-value what we have while idealising what we don’t. But sometimes, the grass really is greener on the other side.

In my last relationship, I thought I was happy, but then I met a girl who showed me what real happiness meant. Melody came into my life one evening and, straight away, I felt like I knew her.

From then on, I never missed her weather forecasts on ITV – she forecast the clearing showers of my heart and when she insisted that it would be “becoming fine”, I knew she was talking straight to me.

Perhaps understandably, my girlfriend grew jealous and left me. But I felt like a whole other dimension, a different kind of love, had been revealed to me.

Be careful not to under-value the value of what you have while idealising what you don’t. But if your feelings are true, as mine were for my 6pm siren, then you can’t deny them.

» Got a sex or relationship worry? Email dearreuben@tntmagazine.com