One of the most devastating things you can discover is that your husband, wife or partner is having an affair.
And suspecting - but not knowing - that your other half is being unfaithful can be even more devastating.
Cheating partners become good at hiding their tracks although they are some telltale signs, according to detective Daniel Shaw of national private investigators Carter Harris .
Shaw boasts that his speciality is catching love rats.
Among his recent clients was Gill who believed her husband was up to no good but couldn't prove it.
But Shaw said proving his infidelity wasn't difficult and Mr Duplicity was soon caught out.
Shaw tells the Birmingham Mail: "Finding out your spouse has betrayed you is and will be one of the darkest moments of your life.
"It didn't take us long to catch him out. When we did it was a simple case of presenting the evidence to her."
Speaking of her feeling throughout this difficult period, Gill recounted: "I didn't want to believe it. It's just a fog of total disbelief. I put some guilt on myself. It's so painful. I just wanted to believe nothing was happened, until I just had to."
"It was life shattering for me, absolutely life shattering. I felt worthless and betrayed."
It was eight years into their marriage that Gill began to notice changes.
"He was so clearly distant, all of a sudden he just wasn't there. He became vacant."
"There was very little conversation and he found many excuses to be away from me. He basically found lots of places to go during the day."
Thankfully for Gill, she has moved on since her divorce and she is free now to pursue her life without living under a pretence.
"It can be a great thing to get rid of someone so toxic in your life that you're living with," she said.
The Tell-Tale Signs
According to Shaw these are some of the signs you need to watch out for:
A partner suddenly caring about his or her appearance when previously they hadn't been so bothered may be a sign that they are trying to look good for someone else.
Love cheats become overly protective of their phones.
They may change their screen unlock codes, keep them permanently on silent and place them on tables and other surfaces with the screen facing down.
Some may even sleep with their mobile phones under their pillows, according to Shaw.
Unfaithful partners will have a litany of excuses why they are coming home late and why they need to be somewhere else other than home.
Shaw concludes: "We look at things such as professional online forensic analysis and detailed background profiling.
"There's a lot of different ways that people can get caught. And they do get caught."