What's it like when you think one of your parents is having an affair? Radio 1 Newsbeat's been chatting to a 25-year-old who spent years suspecting his dad was cheating on his mum - going through feelings of anger, denial and sadness. He's decided to tell his story, anonymously, to try and help others who're going through the same thing.
The phone on the bath
I was 19, and had just got back from a festival.
I went into the bathroom and saw a phone on the side of the bath.
I knew it was my dad's - it was the same phone I'd noticed in his car years before, when I was in my early teens.
Back then I was too young to think anything of it.
But now, I was suspicious.
I picked it up - there was no passcode.
As I started looking through, I saw texts from a woman.
I almost couldn't take any of it in, because I was so angry.
Everything started unravelling in front of my eyes.
But I felt there wasn't enough evidence of an affair - none of the texts were that suggestive.
I had a shower, calmed down a little bit, then went into my room.
I heard my dad coming up the stairs, so I called him in, and showed him the phone.
His initial reaction was: "I don't know what you're talking about."
He took the phone and went downstairs.
Then he came back up with the dog lead and said: "Right, let's go for a chat then."
On the walk, I was nervous. I didn't really confront him very hard.
He basically passed it off as a friend from work who was helping him go through a hard time at work.
"I haven't got many friends, and I didn't think your mum would understand if it was a woman," he said.
In my head at the time, I was basically trying to justify what he was saying.
I had to take his word for it.
He thanked me for reacting well to it, and that was it.
Fast forward two years, and I still had it in the back of my head.
My dad was helping me move into a new flat.
He'd just got a new iPhone, and took a photo of me and sent it to someone.
Later on I texted my mum, asking if he'd sent the photo of me to her. She was like: "What? I didn't get a text from dad."
That triggered something in my brain.
I walked back to him, and saw he was texting someone called Amos.
I knew it was a disguised name, because I would know if he had a friend called Amos.
Dad was staying at mine for the night and I knew I had to get hold of his phone.
So in the middle of the night, I did a Matrix-style crawl across the room, grabbed it and started to go downstairs.
My dad came out of the room and said: "Can I have my phone back please?"
He'd absolutely busted me.
I just made up an excuse about needing it to set up an alarm call.
The next morning, we went for breakfast and then he left - nothing was mentioned.
It was really weird.
Another six months passed, with everything bubbling away in my head.
It was my dad's birthday.
I was walking to the restaurant with mum and dad. We were going to meet my younger sister - but she was running late and dad was getting impatient.
He turned around and started to storm off back home.
I was getting really angry, and followed after him, shouting, calling him a coward.
Suddenly it just came out of me: "Who's Amos?"
He turned around, and his face was totally white.
He basically kept ignoring the question, saying: "Stop talking about this."
Back at the house, neither of us had a key to get in. It was so awkward and I just burst into tears and gave him a hug.
I didn't know what to do.
He knew that I knew something was going on - but we still didn't talk about it.
My mum and sister thought we'd just had an argument. I felt like I couldn't tell my sister because she was still at school.
I had it all on my shoulders.
Alison Cooper, Relationship Counselling Service
Feeling alone and carrying a burden is awful.
If you're in a similar position, you can access relationship counselling for support. Seeing a GP is an option if someone is feeling anxious or panicky.
If you're still at school, college or university, it's worth confiding in a teacher. They would then understand if your behaviour or studies changed during that time.
You could try approaching another family member such as an aunt or uncle and ask them to speak to the parent.
Ultimately I feel having someone you could talk to who would help normalise all those feelings which are associated with loss, would help navigate an incredibly difficult time and help accept that this was not your responsibility.
And then my sister found out
About two years later, I got a text from my sister saying: "Can I give you a call?"
She was absolutely bawling her eyes out.
"Oh my God, dad's cheating on mum," she said.
Like me, she'd got suspicious about his phone and seen the texts to "Amos".
At that point, I felt almost relieved to hear it.
I decided to confront him over the phone.
"Me and my sister both know," I said. "You need to tell mum, otherwise it's going to be very difficult for me to have any kind of relationship with you."
He was just totally silent.
Then at the end of the call he said: "Thanks for telling me."
And that was it.
He didn't speak to my mum straight away.
He didn't even talk to my sister about it, who lived at home at the time.
After three months, he still hadn't told her.
I was at the point where I really wanted to punch my dad.
He was driving me to the train station once, and I just went off on one in the car.
That night, he sent me a text: "I'm leaving tonight, I've left a note in the wall clock. I've asked your sister to get it out on Friday."
I kind of resent him for doing it that way.
But after three months of my sister having to live in a house with them both, I just didn't really care how he did it.
By the time I got to the house, mum had already opened the letter. And that was it.
It's a pretty horrible way to find out after 25 years of marriage.
I don't really have any regrets about how it unfolded.
I think that weirdly, I did everything I could.
I didn't want to be the one that told my mum.
She's not angry with me for knowing all that time - in fact, she was mortified by the fact I'd had to go through that.
I have two main pieces of advice for people going through this.
Firstly, take a step back before doing anything rash.
There were a couple of times where the red mist descended for me - doing things like taking a shower just help me calm things down.
Second, it really helped me to be able to speak to someone privately.
Me and my sister still get on each other's nerves, but it's definitely made our relationship stronger.
The hard thing is how dad's behaved since mum found out.
He'd not been paying her the maintenance and things like that, making life extremely difficult for her.
Little things like demanding my mum return a computer that he'd been given by her parents once for Christmas.
I rang him and told him to stop - my sister got involved too.
The next day, he sent us both a text saying he thought it was best we don't stay in touch.
Mum and dad are getting divorced - and I think he's with the other woman. I'm still working on what relationship we might be able to have in the future.
If you need any help with family relationships, you can click the BBC Advice pages.