People have affairs for many reasons, but none of these reasons are ever excuses.
The fact remains that being unfaithful isn’t something that happens to somebody because something happened to them, it’s something they choose to do. It’s always a choice, never an inevitability, no matter what.
I absolutely agree however, in my personal experience, that no matter how bizarre this seems, going through crises of any sort can pre-empt people to make very bad choices. This is not an excuse, however, obviously not everyone and probably not the vast majority of people respond to crises by having sex with somebody else.
I have to say with hindsight though that it’s interesting that in my own marriage and one of my sibling’s and two of my friends’ marriages, a huge crisis of one sort or another came first before the infidelity. To my knowledge none of those involved had cheated before or ever did again. All couples involved stayed together and seem to enjoy married life, all marriages past the thirty year mark now. Only just occurred to me reading what you said that this was true in all cases I know of.
Affairs are rarely about love, more often it’s about validation when you feel low and self-soothing, chasing dopamine like alcohol or drugs. No excuses though, because having a crisis and feeling low doesn’t give you permission to cheat and get your validation and soothing from a different shoulder to cry on and devastate your family.
OP I think that I and others took that you were staying for the children from the way you worded your original post, and saying that it was a ‘no brainer’ that you would leave if you didn’t have children underlined that.
If you are serious about having a marriage again, or to help you decide whether or not to leave, try the Surviving Infidelity and Affair Recovery websites, loads of advice and forums there to help you heal from infidelity, decide what to do about it, and what he needs to do if you decide to stay together. There’s no pressure to stay or leave there, just good advice on how to go forward and get past the betrayal either together or apart.
It’s your life, the rest of us can go back to our lives and put he kettle on or watch telly after telling you to blow up yours, we don’t have to live it, you do, so listen to the advice here then make your own mind up, no shame in leaving or deciding to try again. Information is key now, especially from him.
In a nutshell, you need:
Truth about what happened, abject apology and understanding of the huge damage he has done, full accountability and transparency, no blame-shifting. You need to see actions which show major remorse and commitment, his dedication to honesty and rebuilding trust, whatever that takes, plus deep introspection, preferably with help from a counsellor, to understand why his response to his crisis was to have an affair.
None of the above happens overnight or without pain and hard work, and it will take both of you committed to improving your relationship to get through.
You have to really, really want this, I only stayed because we had such a good marriage before the affair plus he’d never (to my knowledge) been unfaithful before and it wasn’t worth throwing all that away for what he did. His affair didn’t make him Satan, he was however a totally selfish and colossally stupid arsehole, he’s very fortunate indeed to have been given a second chance after the hell he put me through and any whiff of anything less than putting me and his family first and I’m done.
Set your stall out of what you expect from him with firm boundaries if you want to give him a second chance. You can change your mind whenever you like, he doesn’t get to dictate what happens next, you do.