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“But…why?” is the question often asked after hearing about a marriage breakdown. It’s a question that goes unanswered as the truth is usually too painful to discuss.

Redditors have offered us a sneak-peek in to their deepest, most private reasons for ending a marriage.

1. An open marriage that… isn’t.

“My wife wanted an open marriage. She has had multiple boyfriends/sexual partners. As soon as I try to partake in the open marriage, she flips out. Turns out the open marriage was only supposed to work one way.”

2. Changing after marriage.

“He became a totally different person after we got married. He became very controlling and manipulative…I didn’t want to go home because I didn’t know if I was walking into Dr. Jekyll or Mr. Hyde.”

There’s hundreds of reasons to break up. Here are just some. (Post continues after video.)

3. Abusive behaviour.

“She threw a pot of boiling water at me. It was thrown over our five year old son. She threw it at me because I was paying more attention to my son than her, I had just gotten home from work and he asked me to play the Nintendo with him.”

4. Porn addiction.

“I’m not against porn, but I discovered that he literally spent every waking hour that he wasn’t working copying porn DVDs. Six to eight hours a day of copying porn. And he’d call in sick easily once a week to spend more time with the porn.” What’s worse, her husband had a $30,000 credit card debt from various porn websites and online shops.

5. Getting pregnant during an affair.

“After about a month of her ignoring me I found out through a mutual friend that she had been screwing her boss and had gotten pregnant and that’s why she left.”

Celebrities talking about their break ups.

Jennifer Aniston.It was possibly one of the most talked about Hollywood break ups - Jen and Brad. In an interview with Vanity Fair Jen shared her experience, "There are many stages of grief. It's sad, something coming to an end. It cracks you open, in a waycracks you open to feeling. When you try to avoid the pain, it creates greater pain. I'm a human being, having a human experience in front of the world. I wish it weren't in front of the world. I try really hard to rise above it." Image via WikiCommons.

Rita Ora.

Rita discussed her break up with Calvin Harris in Marie Claire, "It was more of a thing where I was in awe. I was at that point in my relationship where I felt he could do no wrong. I thought he had my back and that he'd never steer me wrong. But then 'I Will Never Let You Down' came out, and everything started to go a bit weird. I don't know if it was because business was mixed with personal or what." Image via Instagram (@ritaora).

Demi Moore.

Demi Moore discussed her breakup with Ashton Kutcher with Harpers Bazar - "I used to think that what scared me was the idea of being abandoned until someone said to me, 'Only children can be abandoned. Adults can't be abandoned because we have a choice. Children don't have a choice.' So I started to rethink. 'OK, it's not that. What's the underlying thread that really scares me?' I think what scares me is not having the courage to reach my full potential." Image via Twitter (@justdemi).

Kim Kardashian.

On her website, KimKardashian.com Kim shared her breakup with Kris Humphries, "I felt like I was on a fast roller coaster and couldn't get off when now I know I probably should have. I got caught up with the hoopla and the filming of the TV show that when I probably should have ended my relationship, I didn't know how to and didn't want to disappoint a lot of people." Image via Instagram.

J-Lo.

"It felt like my heart had been torn out of my chest." - Jennifer Lopez on Ben Affleck, in her memoir True Love. Image via Instagram.

Reese Witherspoon"[Divorce is] very humiliating and very isolating... But, by the way, if it's not painful, maybe it wasn't the right decision to marry to begin with." - Elle Magazine. Image via WikiCommons.

Cameron Diaz.

"When I was going through a bit of a heartbreak a little while ago, I said to a friend, 'Wow, this really hurts!' And he said to me, 'That just shows you what your capacity for loving is.' I would rather have my heart broken a thousand times than never to love at all. I have so much love to give I'm not empty of love, I'm full of love." - Cameron discussing her break up with Alex Rodriguez in InStyle. Image via Instagram.

Katy Perry.

During an interview on The Project Katy discussed her break up with Russell Brand - "Sometimes you can be blinded by your extreme emotions. I definitely was looking for answers during that time I wrote that song ["The Grace of God"]. And yeah, I was depressed, and it was sad, and there were thoughts, but there were never actions, thankfully." Image via Instagram.

Taylor Swift.

"There's just been this earth-shattering, not recent, but absolute crash-and-burn heartbreak, and that will turn out to be what the next album is about. The only way that I can feel better about myself pull myself out of that awful pain of losing someone is writing songs about it to get some sort of clarity." - Taylor Swift, Vogue. Image via Instagram.

Emma Stone."I was crawling on the floor. I remember throwing up. I remember being on the floor... I have never felt anything quite like that. It was so visceral. It's like someone has killed you and you have to live through it and watch it happen. It was awful." - Emma Stone on her first heartbreak, Interview. Image via WikiCommons.

6. Shared tragedy.

“My wife stopped loving me after our daughter died.”

7. Committing too young.

“My ex and I got married very young. I was 15 and he was 17. We were together 11 years and loved each other, but realised we weren’t letting each other grow up. Staying a teenager forever isn’t an option when you’ve got kids. It’s been five years and we still care about each other. We’ve both moved on, he’s a great dad. He and his fiancee are my youngest sons godparents and they are having my goddaughter in January.”

8. Too much friendship, not enough sex.

“After four years without sex we knew it was dead. We had two great kids but were just two roommates raising kids together.”

What are some other real reasons for ending a marriage?