I'm not sure what to really say here other than what's on the tin.

Bit of a long one with a TL;DR at the end.

My wife and I had been together for 6 years, and I will straight away say even if she made a mistake, she is not a bad person. While I had at times been a horrible partner, she was respectful, caring, loving and empathetic. She had been battling with undiagnosed ADHD/Autism, which may have been the cause for a lot of her actions and habits that, in hind-sight, should have been clear as her husband to see. I will also add that while I did all of the cooking every day, and most of the cleaning, she contributed as hard as she could given her condition and struggles and to her credit, really was improving. I also struggled to get over the past her where for 4 years I felt like her slave doing everything around the house until I broke down. This meant at times I would throw her old bad habits at her when I was in a bad mood, which is a shit thing to do as a partner.

The issue, while we had all of our ups and downs, there was a break-down of communication of her needs from me. Apparently she felt disconnected from me and began forming a bond with a guy she met online on the MMO game we play together. Over the next 4 weeks, she would be up until 8am in the morning chatting with him, and avoiding topics when I asked what on earth they would be talking about for that long.

The red flags in my own head started shining the next day after I mentioned I wasn't comfortable. When she stopped talking to him, the next day she was irritable, anxious, angry and I had thought there was something more critical happening like an anxiety attack or if I had said something wrong.

She then let slip that when she had to stop talking to her friend, that "they had something special" and to me that was enough to mark that it wasn't just a friendship anymore. However, she insists it was. This is where I need to know if I fucked up royally: we had agreed at the start of our relationship and constantly throughout it that an emotional affair was just as bad, if not worse than a physical affair because it was the heart on the line. Because of that wording, over the next few weeks as hard as I tried, I couldn't forgive her.

I had tried constantly to try and get through it, but then seeing so many reddit posts on relationships that seemed to show once an EA happens it's possible again, I got jaded and felt that the promise of marriage wasn't worth it if they could get in their words "just a crush" on a friend in such a short period of time. If I had not asked them to stop, how much further than a crush would it go if they already 'had something special'.

I'm going to say this again, aside from this, she has been an ideal partner. There are a few habits she formed because I spoiled her too much and with her undiagnosed ADHD, I feel this was a losing battle and I can't find it in me to stay around because of the broken promise.

It was one night this week I couldn't take it anymore and I've given her one week and I'm moving out, I've already made sure the rent is paid a good month and a half ahead so she can focus on herself and costs before rent is due. (She earns as much as I do which is enough to pay for rent and groceries.) I made sure all the utilities are paid up in advance before swapping it to her name. I've filled the freezer with frozen food she would like as I won't be around to cook for her, and put her favourite juices in the fridge because she isn't eating or drinking. I can't stop wanting to look after her, she made a mistake and caught some feelings for another man. Aside from that, she was a good person, but I can't do this and I believe she deserves a man with better strength. She is absolutely broken and crying constantly, and I'm fucking broken and crying constantly as well. How the fuck do I live without someone who gave a piece of their emotions to another man and is clearly regretting it? Should I have actually just ignored our boundaries?

TL;DR
6 years, amazing partner with some minor flaws due to an undiagnosed condition and bad habits from me spoiling them. Improved and did more things that meant the world to me. She felt alone, chatted with another guy, "had something special" and said 'it was just a crush'. We had already agreed an emotional affair is game over for the marriage. I've prepared to move to another state in a week with making sure she is prepared and has what she needs as far as possible. We're both fucked emotionally and she wants me to fight for the marriage which hasn't even been longer than 1 year. I can't because it was a rule we both said was clear and she should have communicated with me.

Also, no, I am not splitting assets. I've signed the car over to her and she can keep all the savings, I just needed enough to put a bond down for a single studio in another state where I moved from to be with her. She has been a great person and I will want her to have as much support as she can, mistake or not, she's still someone I loved so deeply, but that solid rule was set in place as the end of a relationship, that's it and I can't accept moving the goalpost. I fucking miss her already and I haven't left yet and I can't stop crying.