Sister-in-law angst: The surprising third wheel in your relationship

Forget the dreaded mother-in-law, it seems big and little sisters are barging in on your home turf and affecting your relationship with your wife, partner and girlfriend.

Dating and relationship coach Sarah Davis says bossy sisters are doing more than sticking their nose in their brother's relationship, many extending advice or wanting financial help and it's ruffling the feathers in the love nest.

Peter, not his real name, was married to Anita for five years. The couple split six months ago and have one child together. According to Peter, his marriage started to deteriorate when he found out his wife was financially assisting her sister with small amounts of cash and credit card purchases without being transparent with him.

Family feud

"One thing led to another and it was one of the main reasons why we started to fight," says Peter.

"I had the classic stereotype of a monster sister-in-law who was always in my wife's ear that she needed a loan to help pay for kids text books, pay the rent, needed petrol money and the promise she would pay the amounts back, but it never happened," he says.

I didn't think another woman like a sister-in-law would be the reason my marriage would end

"The moral of the story is my sister-in-law became someone I loathed and couldn't handle seeing – even at family functions. On the occasions I did speak up and address the pressure she was putting on my wife and our family, she made it out as though I was the odd one with a problem. I felt my wife hid secrets from me because she felt obliged to help a sibling – we started to pick on one another and it led to us deciding to be apart," he says.

"It was a nightmare but I didn't think another woman like a sister-in-law would be the reason my marriage would end," he says.

Two sides to the story

While modern family dramas are usually saved for great TV viewing, it's not uncommon to see everyday relationship dynamics become fraught when a family member gets in the way. In the case of Peter, his marriage ended, but many couples continue to exist with much personal angst and less communication.

"I often see a brother side with a sister over their partner because it comes down to a basic need for approval," says Davis.


"Men often look for approval by the women in their family – whether that's a mother or sister because that gives them validation that they have made a good choice," she says.

Rival relationships

When Damien Williams met his wife 10 years ago, the pair quickly bonded over their love of the arts and travel. They have three children aged under eight and know too well the pressures on a working family and the juggle of raising one.

Williams is very close to his only sister. It's a relationship he adores and keeps close to his heart, but admits she might show signs of jealousy when he and his wife dine at fine restaurants or take holidays to destinations she'd love to go to – especially as siblings.

"My wife finds my sister's behaviour weird but to me it's just the way it's always been and I value her place in my life and her opinion," says Williams.

"My wife says my sister tries to organise my social calendar. She sees it as my sister making her stay home to mind the kids but I don't see it as intentional," he says. "It's just a bit of brother and sister time."

Collaborators and co-conspirators

Author Jeff Kluger has written many books about the power of siblings– his most notable is The Sibling Bond. Brothers and sisters clearly shape who we are. As Kluger recently wrote in Time Magazine:

"From the time they are born, our brothers and sisters are our collaborators and co-conspirators, our role models and cautionary tales. They are our scolds, protectors, goads, tormentors, playmates, counselors, sources of envy, objects of pride," says Kluger.

Davis agrees with Kluger but adds that family love aside, men have chosen a new woman in their life now and need to make her feel valued.

"It's important to tell your partner you love them and that they are number one," says Davis.

Intimidation zone

Robert Ng, 35 is single and says his sisters have always been protective. He is the youngest and only brother of three siblings and says when it comes to introducing his partner to his family it's his sisters who become clingy.

"Sisters can be really intimidating to your prospective partner," says Ng.

"I can only say this now that I am not in a relationship, but the women I have dated have all commented on the way they feel my sisters were a third wheel in the relationship. They are ever curious and especially demanding on festive occasions as to who sits where at the dinner table."

The toxic triangle

Timothy O'Leary has been counselling couples for 13 years. He's seen all sides of the relationship spectrum come into play – from affairs to in-laws causing problems.

O'Leary says couples need to make each other a priority. "That's not to say men won't be caught between a rock and a hard place when it comes to juggling divided loyalties between a sister and partner," says O'Leary. "But it's important to keep the communication flowing.

"When men have a life-long affiliation with an older sister and have been taking advice from her for many years you will find these men won't want to be disrespectful to her," says O'Leary.

O'Leary calls it a toxic triangle – where everybody hurts, sometimes.

But the traumas of the past needn't weigh you down – it's all about looking at the bigger picture and telling someone how much you love them.

Has your sister ever come between you and a significant other? Share your experience in the comments section below.