I broke the rules of our open relationship by lying – how do I fix this?

DEAR DEIDRE: EVEN though we’re in an open relationship, I didn’t come clean with my partner about sleeping with a friend, and my lie is tearing us apart.

She isn’t angry that I had sex with this woman — she’s angry that I wasn’t honest about it.

We have been in a relationship for a year. I’m 30 and she’s 28.

Until I screwed up, it was working brilliantly.

We agreed from the start we were both free to sleep with other people.

Both of us have huge sexual appetites and keeping the relationship open means it never gets stale and we don’t need to cheat.

Our sex life is special because we love each other.

Each of us drew up a list of “allowed” people — a sort of contract.

We agreed that if we had sex with someone else, we would be open about it. We didn’t need to know details.

But a month ago, my partner went to stay with her parents for the weekend.

I met a group of friends, including someone on my list, and ended up going home with her.

When my partner got back, she asked about the weekend, and if I’d slept with anyone.

I don’t know what possessed me, but I said No.

She must have sensed I was being awkward because she asked a few more times, but I was trapped by my lie, and had to lie again.

I didn’t know that another friend had told my partner I’d gone home with the other woman.

A week later, she blew up at me. She said she knew I’d repeatedly lied.

I confessed everything, but it wasn’t enough.

She says the sex isn’t the issue, it’s my dishonesty.

She believes I must have feelings for the other woman — which I genuinely don’t.

She says she can’t trust me any more and doesn’t think we can continue the relationship.

How can I win back her trust?

DEIDRE SAYS: You are human, you made a mistake and you are truly sorry for it.

But you need to think about why you lied.

Be honest with yourself so you can be honest with your partner too.

Perhaps you were protecting her feelings because you felt – consciously or unconsciously – that you’d crossed a line with the other woman.

Or maybe being in an open relationship isn’t making you happy any more.

If you both want to repair your relationship, it can be done. But rebuilding trust isn’t easy and takes time.

Talk to your partner and tell her how much you love her, and that you want to sort things out.

It could be time to redraw the boundaries of your relationship.

My support pack, Looking After Your Relationship, should help you to make the changes needed to get things back on track.