Not all warning signs are glaringly obvious, as these stories show
Common relationship wisdom states that they have to be built on trust, while also letting your partner have the independence they need.
Unfortunately, sometimes trust can be tested to breaking point, and independence can be abused.
It's not easy to address signs something is amiss in your once-happy relationship.
Admitting it to yourself is unpleasant. As for confiding your worries to others, what we sense and perceive can be so nuanced and personal, the relationship 'outsider' may not always agree there's a problem.
But short of catching someone in the act, or lipstick-on-collar clichés, is there a way of telling if you're partner is being unfaithful ?
According to some people, there were sure signs. Sharing their wisdom on Quora , users have revealed the moment they knew something wasn't right.
1. Body language
Facebook can be misleading, as you seldom get the full story from photos, but as an anonymous writer explains, sometimes the devil really is in the detail.
"I was casually browsing Facebook when I saw a photo my wife has been tagged in - a group photo from a work/social function.
"There was a guy with his hand on my wife's shoulder, which is, under circumstances, innocent enough since a bunch of people have their hands on someone else's shoulder.
"But I'm the only person who knows my wife will go to great lengths to not be touched by anyone she is not close to ( a very limited circle of me, her parents, and her best friend).
"I'm not a paranoid / jealous type. But, knowing my wife, this was an immediate red flag.
"Over the next week I went over her chats and emails (we never kept passwords from each other).
"The guy from the photo was one of three on/off lovers she had at the moment."
2. Two phones
Another anonymous user described how her boyfriend's shifty phone behaviour caused warning bells to go off.
"We were together for five years then, and in a long distance relationship.
"He was visiting me where I was working and staying at my place.
"My boyfriend had two phones (battery). He was always very protective about his phones (he would even take them to the washroom) - RED FLAG!
"On the day he was supposed to leave, he left one phone outside while having a shower. I was just generally browsing through it and found romantic messenger exchanges between him and his 'friend'.
"I told him to leave and never to return. He persisted and begged for a chance. I gave him that chance.
"It's been two years since that incident, it's taken a while to rebuild some of the trust (he has been extremely transparent), but we are getting there!"
3. Hunch
Another user who preferred to remain anonymous described an unshakable gut feeling.
"I just knew something was off.
"When we had been married around seven years I got really sick. The illness lasted for about a year. It started during this time.
"After a year of questioning my sanity I straight up asked her. She got in a huff and said 'I can’t believe you are accusing me of having an affair'.
"Notably she did not outright deny it. OK, alarm bells still ringing.
"Months later I found proof in the form of condoms. We did not use condoms. Condoms have expiration dates. You can trace back the date they were bought.
"She was away for 2 weeks. I sat down and had a hard think. She returned. I confronted her. She lied. I gave her proof. She confessed. I filed for divorce.
"Some advice: Human beings are highly perceptive if we let ourselves be. That is how we survive.
"If your gut is constantly telling you something is wrong, there is probably something wrong. I thought I was absolutely insane during this period. No, I am just perceptive."
4. Cold and distant
Judy Dodd recalled a waning warmth and affection from her then partner while they were in a long distance relationship.
"He was working in a different state but would come home every weekend. This out of state business was only supposed to last three months.
"As time went on I could feel him being more distant.
"He would arrive home on Friday evening and I’d be excited to see him and wrap my arms around him and all I'd get in return was the 'one arm hug'.
"I thought I just needed to try harder.
"His out of state business wasn't ending and I started to notice that although every weekend he took clothes to Minnesota he didn't bring as many back.
"One Saturday morning he went to get a haircut. I was hanging his clothes up in his closet, like a 'good little wife', and noticed his opened briefcase.
"Lying on top of his open briefcase was what looked like a card in a blank envelope. My first thought was 'OH he must have bought me a card, I really did think that, sad.
"Even now, 22 years later I can still picture myself in that closet opening that card.
"Inside the 'evil witch' had written a rather lengthy note about how wonderful he was and how wonderful last night was and blah blah blah.
"The killer for me was she signed it 'Happy Anniversary, Love D'. Anniversary?'
(Source: Mirror)