Writer and broadcaster

My fiance’s sister is jealous and talks about me behind my back. The Guardian.

Dear Annalisa

I met my fiance on a blind date about five years ago – we moved in together after a year of dating, bought a house after a year and then he proposed after being together for four years. When we first met and began dating, his sister lived away. She moved back home after he and I began living together. It was clear that she and I did not get along.

Going through the normal awkward family events, his sister doesn’t like the same things we do. We have tried inviting her to things but she’s uninterested and shows everyone videos on her phone exclaiming each time “Isn’t that funny?!” (Of course, she doesn’t show me until I ask.)

Their mother and I got along and now we don’t – my fiance is sick of me complaining. I am not quite sure what to do. He supports me in that he affirms his sister is jealous of all his girlfriends, but does nothing to help remedy her behaviour. The mum said she wants us to have a therapeutic mediation and I had to talk my fiance into it because he thinks his sister is just acting out. But she’s telling people very hurtful things about me. I just want to confront the problem because clearly his sister is hiding behind their mother. On top of all of this, it’s six months until we get married.

I’m beginning to think I just need to cancel the wedding. I want a family to want me, not talk about me behind my back.

The situation you describe is more common than you think, with sibling relationships interfering with married ones and the sibling who is married trying to keep their spouse happy and also the sibling. The jealousy seems to be more acute when it’s opposite-sex siblings but you can also get same-sex siblings causing havoc.

I contacted Stella Vaines, a psychoanalytical couples psychotherapist (bpc.org.uk). Vaines explains that “sibling relationships tend to get over-determined when there is not much parental presence” – especially the parent of the opposite sex. In this case, it appears your fiance’s sister is the one with more of an attachment to her brother and Vaines thinks it significant that there’s no mention of the father.

Is he around? Was your fiance a father figure to his sister more than a sibling? Is guilt, I wonder, playing a part here? Does he feel disloyal to his sister by “going off”?

Vaines also wonders if your fiance has found someone – you – who could give voice to his own “disowned feelings”. In other words, he may have found someone who can “vocalise his own feelings [about his sister], someone who won’t put up with the situation”.

He may have done this because he can’t himself say how he feels for all sorts of complicated reasons – maybe to do so would cause too much upset in the family.

But you, too, need to look at why you are with someone who, as Vaines puts it, “can’t put you first”. Is this a pattern you are repeating, something you are used to, perhaps? You do need to look at what the situation is triggering in you. Not because you are to blame for it (you’re not), but it may help you to reach an understanding and therefore a resolution. If something in this weren’t hitting a nerve, your fiance’s sister’s actions would, largely, short circuit.

An ultimatum – however easy it is for others to prescribe – is not really the answer. I asked Vaines how your fiance might be feeling and she thinks he would be feeling very torn. If you force him to choose, this will sow the seeds for huge resentment and drive a wedge between you and the rest of the family. I hope that such drastic action won’t be necessary.

“What I find interesting,” says Vaines, “is that you are looking to the mother for a solution. If you want to be a grown-up couple, you need to separate out [both of you] from your family of origin. You need to explore these issues together. There is no quick fix, but if with some couples therapy, your fiance comes to an understanding [about his relationship with his sister] something will shift within him. He can still be loving towards her but he can become more assertive.”

I do think your fiance needs to take more responsibility for what’s happening and to stop being so passive. You can’t force him to do this. You can, however, choose whether or not to put up with the situation. You do need to be careful of not becoming the “third sibling” with the mother lording it over the three of you.

If you walk away from this relationship – entirely your choice – it needs to be because you want to. Not because you’ve been pushed out by his sister. Also, as Vaines says: “If you don’t get a better understanding of situations like these, they will just recreate themselves. Your fiance will continue to find his sister a problem and you may find yourself in a similar situation. This does speak to something unresolved in each of you.”

If you’re not sure about marrying, there is a third choice between stay or cancel: postpone.

This article first appeared in The Guardian Family section on 23 April 2016.