I struggle with my relationship with my brother-in-law. He is sarcastic, critical and aggressive towards me, my mum and, at times, my sister. Most of my family see it as an inferiority complex and ignore his behaviour, but I struggle to accept it. I don’t want to upset my sister, and I know she’s in a difficult position and feeling vulnerable after the birth of their first child, but I’m disappointed she doesn’t stand up to him, or for me or our mum. He doesn’t behave like that in front of his family or our father. My sister says he’s stressed, but I feel that’s no excuse. My sister and I are both “people-pleasers” who don’t like conflict (our parents are divorced and they used to argue a lot). I feel that I should stand up for myself and take a stance, but I could damage my relationship with my sister. I don’t know if I should just accept that my sister has chosen her husband and put up with and accept him.

I suspect that, at heart, this is not a problem about your brother-in-law. It seems more likely it is a question about your struggle with confidence and assertion. You say your family dismiss your brother-in-law’s behaviour as an inferiority complex and simply ignore it. The question is, why can’t you? What is it about his attitude that makes you so angry when the people around you hardly notice? Or, if they do notice, are not bothered by it?

In therapy, when somebody triggers us (provokes us to overreact), it is often because something in that person’s behaviour mirrors a quality in ourselves that we don’t like or are afraid of. It may also provoke envy because, secretly, we would like to behave in the same way, but are frightened of the consequences.

I am not for a moment suggesting that you are sarcastic, critical and aggressive, although I wonder if you would like to be free to express a bit more anger but feel you must keep that urge hidden because you are (as you say yourself) a people-pleaser? There is a part of you that would like to get away with the kind of behaviour your brother-in-law manifests. You would like, occasionally, to be stroppy and shout and put yourself first, but you don’t dare because you believe that if you did, people wouldn’t like you.

This is sometimes called “good girl” syndrome. On the surface, we behave as if we are sweet, kind and considerate. We don’t like to rock the boat or ask for what we want or need because we can’t bear conflict, particularly if we have grown up seeing rather too much of it. So we learn to keep the peace, or become the peacemaker, by putting our own wants and needs aside (including the need to express anger). We sit on our most difficult and hostile emotions and bottle them up behind a compliant exterior until something triggers us.

As we have never learnt how to show anger or be assertive, we don’t know how to express our needs in a healthy, moderate way. Rather than simply asking somebody to stop doing something upsetting, or explaining that their behaviour is unacceptable, we either explode — or fear that we will — or we clamp down on our rage. That part of ourselves is so contrary to the image we would like to present to the world, it makes us feel ashamed and guilty, which creates yet more unexpressed resentment. This is the passive-aggressive model.

I wonder if you are the peacemaker in your family, and grew up trying to protect your sister and mother, so the sight of your brother-in-law being rude triggers your feelings of protectiveness. You take so much responsibility for their feelings that you don’t believe they are capable of standing up for themselves. If you are hyper-alert to the idea they might be hurt, you may find it impossible to understand why they don’t even notice what you see as offensive behaviour.

It’s all very good to understand your impulses, but how do you deal with them? First, you might consider an anger-management course. They are not just for people who are obviously hostile, but teach us how to express anger in a healthy way. You might also consider the Buddhist ideals that teach us, first and foremost, compassion for ourselves. Once we have mastered that difficult art, we begin to understand that everyone is suffering equally behind a facade (your brother-in-law’s facade is anger, yours is compliance and people-pleasing) and that we can have compassion for them, too. It certainly takes the sting out of other people’s behaviour to realise that we all struggle with emotions that overwhelm us. In that spirit, I am going to recommend two books. I do hope they help.

The Wisdom of No Escape: How to Love Yourself and Your World by Pema Chodron (Element, £8.99).

Beating Anger: The Eight Point Plan for Coping with Rage by Mike Fisher (Rider, £7.99)

If you have a relationship question for Sally, e-mail sally.brampton@sunday-times.co.uk . In case of publication, names will be withheld. We’re sorry, but Sally cannot answer letters personally

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