I was in a somewhat similar situation. After I graduated college, my wife and I moved thousands of miles away from where we lived (and where we were both from) so I could get a job that involved my major. However, she absolutely hated it where we moved to, so to try to make her happy, I tried to find another job that was closer to our hometown and her family. While I was looking, we agreed that she would move back in with her parents so she could start lining up a place to live when I got a job offer. Of course, I didn't know that when she went to her parents, she started an affair with another guy. She strung me along until I did find a job, and just after we moved, she told me about it. She said it wasn't sexual, but there was "kissing and touching".
Needless to say, I already was in a bad spot, because I dropped out of high school and busted my ass to get my original job offer (bad location, but awesome work there). She said she wanted to stay with me. So I rugswept to try to keep the status quo. That was my biggest mistake, as she was still talking and sending nude pictures to this guy for 6 months after our "reconciliation". I didn't find out about the extent of her communication with this guy until well after we separated. DDay happened in late 2009 by the way.
Fast forward a few years. I spent years being numb, and it seems the passion of our marriage went away. We had a kid in 2010, so I thought it was just the parenting thing. I even remember around 2012 or so, I told her that our relationship felt empty, and that we should consider divorce, but I just chalked that up to depression and stuck around.
I was in a deep existential depression basically all of 2014, and probably longer than that. In early 2015, she says she wants out, ILYBNILWY, etc. It wasn't until June that I find out that she had another guy lined up, and the extent of her relationship with the first guy.
This is long winded, I know, but after she said she wanted out, I was beating myself up, thinking that I tried everything to make her happy and it still wasn't good enough, so it must be a personal failing on my part. I suffered from depression for years, some of it due to my shitty upbringing, and some of it due to the cheating. I'll tell you what, though, after I found out why she REALLY wanted out, everything turned around. I'm still working through the anger of her betrayal, but I've found I enjoy life and my job a lot more. I don't take my self-loathing out on my son anymore. I'm much happier not being in that situation, which all started with that toxic resentment.
Please don't make yourself suffer any more. You did nothing wrong. For you own sake, I think you should leave. It's scary, I know. I was scared too. And worrying about the kids and how they will react is another concern. But let me tell you, even though doing the 50/50 custody with an autistic child can be difficult, he's in a better spot now that I am in a better spot. Your kids will adjust and adapt, and after the initial shock, will also be in better spots because you're in a better spot. As for your wife, well, she fucked up, and now she has to reap what she sowed.
[This message edited by digitaldrifter at 9:09 AM, January 15th (Friday)]