Dear Annalisa

Eleven years ago, I left my wife of four years for her best friend. We were in our late 20s. It was a very difficult period for everyone concerned. My ex-wife moved away and severed links with us. We eventually got married and had two children and have been happy together. We were relieved that my ex later remarried and had a child.

Recently, my wife was diagnosed with cancer. The prognosis is favourable but she is in very low spirits. Worst of all she has convinced herself that her cancer was a punishment for the pain she caused her former friend.

She feels that she needs to be forgiven in order to have the strength to get better and wants to contact my ex. I will do everything I can to help and support her, but am very much afraid of the effect rejection would have in her fragile and vulnerable condition.

A mutual acquaintance told me a while ago that, as far as my ex-wife is concerned, we are dead. Also, I’m aware that she doesn’t owe us anything. What to do?

I’m very sorry to hear about your wife’s cancer. Of course it is not a punishment and your ex-wife’s forgiveness cannot bestow a magic cure. But, I understand the power of these things. When we face serious illness, and the prospect of our own mortality, there can be a desire to right wrongs. Your wife may also, without perhaps realising it, miss her best friend and the events of 11 years ago might only now be hitting her. However, your ex-wife will not have this perspective.

In order to know what to do, in times of great emotion, I find it helps to look at things practically.

The situation, as you have told me, is that your wife wants her former best friend’s forgiveness and yet it is not in her power to just have it, she must ask for it and you fear that the rejection will have an adverse affect on her. You could write to your ex-wife yourself, of course, but I got the impression from your letter that this was something your wife wanted to be directly involved in and I think it is better if this is between the two of them.

You are right to say your ex does not owe you anything. Your wife seems to think of this as a potentially clean transaction: write to my former best friend, she will forgive me, it will give me the strength to get on with dealing with my cancer. This is the hoped for response but, even if that scenario were to happen, I wonder if you have thought beyond this. Your ex may not phrase the forgiveness (if it is indeed forthcoming) in the way your wife wants or needs. And of course, the reaction may be quite the opposite.

While your thoughts are understandably with your wife at the moment, I would also counsel you to think about the impact this would have on your ex-wife, too. Getting a letter from her former best friend saying she has cancer and wants to be forgiven puts her in an unenviable, perhaps impossible, situation. What if she doesn’t want to forgive but feels forced to? Is a faux absolution valid? If she ignores your request, or rejects it, that will not only make you all feel worse, but I doubt it will make your ex feel great about herself either. I don’t think that’s a fair position to put her in, given that she doesn’t hold the actual cure for your wife’s cancer.

Nowhere in your letter (unedited this week) does it mention saying sorry, only being forgiven. Using the passive rather than the active. I am not judging any of you – life is messy and relationships are complicated – but it’s an interesting absence. In seeking forgiveness it’s a good idea to say sorry, first. This is in your wife’s power, something she has control over and which will, hopefully, give her strength.

If your wife wants to do anything at all I would advise her to write to her friend to say she is sorry for what happened (assuming she is) and leave it at that. Don’t mention forgiveness or the cancer and make it about giving your ex something (an apology) rather than asking for something in return. Otherwise it smacks of her/you both wanting something from your ex to make your lives better. And she may decide she has already given enough.

On a more practical note, I would advise you/your wife to talk through things with a Macmillan nurse (0808 8080000, macmillan.org.uk). They are wonderfully supportive and will talk through any aspect of cancer with you, even the psychological. There’s also Maggie’s, maggiescentres.org, a great organisation which offers emotional support for people affected by cancer.

This article first appeared in The Guardian on 12 September 2014.