I’m worried that my partner’s cold sore is a sign he’s been cheating – should I get checked?

DEAR DEIDRE: I’M worried that my partner’s cold sore is a sign he’s been cheating.

He denies it but I’m not sure if I believe him. How else could he have got it?

I’m 37 and he’s 40. We’ve been together for five years.

A few days ago, a sore appeared on his lip. He says he doesn’t know what it is, or how it got there.

He thinks it’s because he bites his lip, but it looks like a sore to me.

I am now imagining he’s been kissing another woman or, worse, having oral sex.

It bothered me so much I asked him straight: “Have you cheated?”

He got really upset, and said it’s not his fault he has a skin issue.

But I can’t stop thinking he’s been unfaithful.

Now I’m wondering if I should make him get an STI check, and if I need one myself too?

Am I overreacting?

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DEIDRE SAYS: Cold sores are caused by a herpes virus, but not always spread by sexual contact.

They can lie dormant in the body for many years.

Your boyfriend may just be run down. It’s possible, if it is a cold sore, your partner caught the virus as a child.

There’s more information about cold sores on the NHS website ().

Perhaps the bigger problem is that you don’t trust him.

My support pack Looking After Your Relationship should help.