Hit me up: I slept with my sister’s husband and feel awful

Our resident agony aunt, Rhona McAuliffe, advises a reader who has fallen for her sister's husband

Dear Rhona,

I don’t want to give myself away here so am going to be a bit vague with details.   I’ve fallen deeply in love with my sister’s husband and don’t know what to do.  They’ve been having difficulties in their marriage for a while. He feels that she prioritises their kids over him and says they don’t have sex anymore.  She orders him around a lot in public and kind of hisses at him if he does something wrong.  She’s the main breadwinner and he looks after the kids and works from home. 

I’ve had a tough time this past year and suffered with my mental health so have had to take some time off work.  I’ve moved back with my parents, who live very close to my sister’s house.  I started dropping in on my brother-in-law and the kids as something to do but he’s ended up being an amazing support.  The rest of my family are afraid to talk to me about anything and walk around on eggshells, ignoring the series of events that led to me leaving work and moving home. 


My brother-in-law makes a point of checking in with me and really talking about what happened and how I’m feeling.  Conversations with him are my refuge and he always makes me feel better.  He also started opening up to me about his relationship with my sister and we got very real with each other. 

I started calling in when the kids were at nursery and only the second time we were completely alone, we ended up in bed together.  I feel awful, I know I’m inviting huge judgement here, I don’t feel good about myself at all and feel even worst for my sister.  I know what I’m doing doesn’t have a happy ending but our feelings for each other are so strong I can’t just switch off from them.  I believe in true love and destiny and wonder if mine has arrived in the unlikeliest of guises?

Torn, Munster.

Ok, I’d like you to visualise yourself straddling the stout cylinder of a nuclear bomb, ripping through the skies en route to decimate your sister’s life.   In front of you is a control pad with a big yellow button.  That button will reverse the course of the warhead, sending it back into orbit to self-detonate, ejecting you along the way.  I suggest you press the yellow button and prepare to parachute to the wasteland below.  I’m not saying it’s going to be easy, nor am I attempting to diminish your feelings for your brother-in-law (BIL) but I am strongly advocating an immediate retreat from the situation before she blows.

It’s not surprising that you’ve fallen for your BIL.  At a time when your family seem unable to talk openly about the rough year you’ve had and the difficulties you’re still experiencing, your sister’s husband is both available and has been a compassionate, supportive ‘friend.’  He is also the perfect rep for The Forbidden Fruit Theory: that we humans are programmed to desire what we can’t have.  The secret trysts and joint deception breed a special intimacy that is not necessarily indicative of real-world living.

Although you haven’t shared the nature of your mental health struggles, I can only presume that the decision to leave your job and flat, and move back home with your parents temporarily suggests that you are still emotionally tender.  A combination of low self-esteem, a sense of displacement and a hunger for meaningful connections may well have influenced the intensity of your mutual bond from day one.  Again, I’m not belittling what you have together but would be mindful of identifying all contributory factors.  Being open and honest with your therapist is also key here; presuming you are indeed bouncing off someone other than your brother-in-law? If you’re not with a therapist, search the Irish Association for Counsellors & Psychotherapists here for a local practitioner.

It sounds like your sister’s marriage is indeed under strain, with hints of some toxic power-playing.  From various studies, I’ve pulled up, however, between 60% and 80% of married men who have affairs are still in love with their wives but aren’t getting what they ‘need’ at home – love, affection, respect etc.  According to relationship experts, only about 5% of cheating husbands end up with their mistresses.  Now, I’m not suggesting we live and die by these pretty arbitrary stats but I would say that in the case of most infidelities, the odds are stacked against a Disney ending for the emotional interloper.


I also wonder if you’ve really considered the consequences here?  What may feel like the path of least resistance – or your so-called destiny – is, in fact, the most gigantic gamble with no guaranteed pay-off.  Although most cheaters think that they will never be caught, there’s a chance your sister already suspects something.  Regardless of how you want it to go down, once the revelation breaks, all bets are off.   Whether your sister neuters her husband in his sleep, sells his car on Ebay or publicly outs the affair on a 96-sheet billboard, it’s entirely out of your control.  As is BIL’s reaction.  Seeing his wife so distressed, and facing the destruction he has caused, he may plead with her to work things out, with a focus on counselling, a stable home for the kids and reinventing their marriage.  It’s common for the faithful partner, on exposing an affair, to experience depression, anxiety, intense shame, guilt and raging anger.  All of which is likely to be amplified with the double-betrayal.  We are inclined to help our tribe rather than hinder them so your involvement will pack a staggering gut punch.

Meanwhile, as carnage ensues, you may well be ostracised by your entire family, not just your sister. Unless you are a clinically diagnosed sociopath or narcissist, which sounds unlikely, your resultant isolation may lead to deep remorse, guilt and bouts of depression.  There is no winner in this situation, no matter the outcome.

The great news is, you still have time to shut the affair down, back up the nuke and skip town.  That may mean borrowing money from your folks to go travelling, couch-surfing with friends for a while or flinging yourself at a new hobby – what about Jujitsu? Sever all contact with your BIL, try to stop deifying him and focus instead on his character flaws.  Number 1: he had an affair with his wife’s sister.  Just let that settle.  Continue your counselling but don’t feel the need to confess to your sister or family.  Try to put it behind you and move on.  I know this is far easier said than done but hopefully one day you will be able to pat yourself on the back for your sterling work in the trenches.

Apologies for not giving you an easy ‘out.’  I try to be as objective as possible but can only see the fall-out here, the trail of bleeding hearts.  If it makes you feel any better, I did discuss this problem with my husband, who’s a solid, sage-like character.  He was more into exploring the truth of your relationship with your brother-in-law and its propensity to survive in abject isolation.

If you’re anything like comedian and writer, Stephen Fry, social purgatory may actually hold some allure for you.  While touring a Mormon temple he was told that in the Mormon faith, the afterlife held the promise of an eternity with all of your family.  He replied: ‘And where do you go if you’re good?’

Rhona McAuliffe might not be a trained therapist but she does have very big ears, quite a long nose and a gaping heart.  If you have a problem that won’t just go away, she’d love to hear it.  Write to Rhona at [email protected]


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