File photo: A couple

Dear Coleen,

My boyfriend and I have always been very open and experimental when it comes to sex, and over the past few months, we’ve been having threesomes with one of his good friends.

However, recently, I saw his friend on my own and we ended up in bed together, which is breaking all the rules we set out at the beginning.

We’ve slept together a few times since and haven’t told my boyfriend, and I’m finding myself becoming more and more attached to him and less so to my boyfriend.

I think I could actually be falling in love.

I’m also feeling very guilty about hiding this from my boyfriend.

Neither of us knows what to do, but we both agree we feel something deeper for each other and that it’s not only about the sex anymore.

Even though my boyfriend was the one who suggested the threesome and brought his friend into it, I know he’ll be devastated if we tell him or he finds out.

I’m feeling confused and don’t know how to get myself out of this mess – have you any ideas?

Coleen Nolan
Coleen Nolan is the Mirror’s resident agony aunt

Coleen says

It’s always a risky area when you make a sexual fantasy like this a reality.

There’s so much potential for jealousy and paranoia and, as you’ve discovered, becoming emotionally attached to the person who’s not your partner.

I think you have to be honest with your boyfriend – you don’t have to tell him that you’ve been sleeping with his friend on the side – but you should admit that you’ve developed feelings for this other guy that goes beyond sex.

Then you have to decide how to move forward. You either decide that sex with this other guy (including the threesomes) can never happen again and you make a proper go of things as a couple, or you end your relationship.

But don’t carry on sleeping with the other guy behind your boyfriend’s back.