As if that weren't hard enough, then there's the really daunting question about what comes next: Should you stay or should you go? Is the relationship worth fighting for?
In some cases, hell-to-the-no.
In others, it may not be the worst idea.
Every situation is different. Here's what happened when these women gave someone a second chance—or received one themselves:
1. 'IT TOOK STUBBORN DETERMINATION'
"It was brutal and horrible. I was totally in disbelief that he would step out when I thought that our marriage was just fine. We had frequent sex, both worked outside of the home, were raising our terrific children, and were living a typical, middle-class Aussie life.
"It was our stubborn determination that pulled us through this without intervention from counsellors or therapists. We both realised that six months of an affair could not trump 25 years of a decent marriage. It really was worth fighting for.
"It has been about six years and I will always carry a small, emotional scar, but what we have now is a more open, honest and compassionate understanding of what we need and want in our relationship. I have learned to trust him again and he has learned how to be more attentive to my needs." —Stacey, 54
2. 'THERAPY (AND LOTS OF IT) HELPED'
"We’d been together for two years and I was getting restless. It wasn’t that I didn’t love my partner anymore, I just felt trapped. We were young and it felt like we’d settled down so soon. I started seeing someone else, a woman from work. It was freeing at the time. Eventually, the guilt got to me and I broke down and told my partner. Instead of leaving me, she wanted to work through it. We’ve been married for five years now and frequently revisit this time in therapy. It takes a lot of effort to get through something like that." — Jessa, 35
3. 'TALKING ABOUT IT WAS CRUCIAL'
"We both cheated and we're working through it. I think it's important to stay rational and have real conversations about the cheating. I would recommend not asking for specific details as it's better not to know. Ask about and explain the 'whys' of why it happened. I also think it's very important to not ALWAYS be talking about the cheating. I think it's important to intersperse good times so that you remember what you are fighting for. I also think it's important not to have sex again until you are ready." —Mary, 32
4. 'I FOCUSED ON MYSELF'
"I had a very hard time when it first happened. He left me for another woman even after knowing him since 5th grade and having a child together. I overcame this by limiting my contact with him and kept any contact we had about our son. I moved all of his stuff into the basement and started focusing on myself. When I started to focus on myself and build my self-esteem back up, I was able to move forward and be happy [with him] again." —Bella*, 48
5. 'IT TOOK A CLEAN BREAK'
"When I found out he’d started seeing someone else while we were together, I left him. We didn’t speak for six months. I didn’t answer his calls, texts, or emails. I even blocked him on social media. Then, we ran into each other at a party for a mutual friend. We got to talking and both realised how much we missed each other. We’re taking things one day at a time, but it’s been three months and so far, so good." —Malia, 27
6. 'WE SPENT TIME APART TO FOCUS ON OURSELVES'
"He found out what I was up to after three months of my sleeping with someone else. He told me he never wanted to see me again. It was then that I realised how badly I had screwed up. I didn’t want to lose him. He didn’t want to lose me either. We spent some time apart, did a lot of therapy and personal growth, and ultimately chose to give it another shot. A few years later, we parted ways on good terms. It just wasn’t working out for either one of us. Everything about the relationship was a learning experience and I’m grateful for it. We decided not to stay friends. It would have been too hard on both of us." —Mia*, 31
7. 'I LAID OUT EXACTLY WHAT I NEEDED'
"My ex left me for another woman. He literally just disappeared and we were living together! I came home from work one day and all of his stuff was gone. I called multiple times and he finally texted me back and told me that he didn't want to be with me anymore. I found another place and stopped talking to him completely for 30 days and then slowly I reached out to him and we started talking again. We are now back together and I have explained what I need from the relationship. He agreed to what I've asked for so we are back together now. But it's a long road of counselling ahead. I'm just trying to forgive and give him a second chance." —Kris, 28
*Names have been changed.
This article originally appeared on Women's Health US