OP many of us have been there where you are now and know how you're feeling.
You are in shock right now so be very gentle with yourself.
Practically make sure you are keeping yourself hydrated and eat bananas or soup or something light when you're able to. Just little steps to take care of yourself while your body is running on adrenaline.
I tried with my XH. We had a newborn and a 7 year old so I felt I had to try to hold onto my marriage. XH worked with OW and that wasn't going to change.
It was a living hell for me and I wish I'd had MN for support at the time, things would have been very different for me. I suppose what happened was what's called 'hysterical bonding' where I did everything to be the woman I thought he wanted and we went through a honeymoon phase as such.
Guess what? XH just carried on as soon as he thought I wasn't looking.
I caught him texting her and this time I booted him the fuck out. Proper bin bags in the street, neighbours all watching kind of thing.
My life is amazing now, I remarried a few years later to a wonderful man.
XH and OW married. I feel no anger, no resentment, nothing now towards him. It's like being married to him happened to someone else now. She doesn't trust him and how can she? She's seen how duplicitous he can be.
You get this one life and you deserve to be happy and find peace. In the coming days, months you will find strength you didn't know you had.
You can absolutely do this on your own, you will surprise yourself.
If I had my time again I wouldn't have taken him back. He acted like a victim and even at the time in the fog of it all, I could see what an utterly selfish cunt of a man he was. I just wouldn't have wasted my time.
I would have my suspicions that this wasn't just a one off with your H and he'd dumped her and that's why she wanted you to know. You and his friend 'warned' him and he ignored you and carried on anyway and you have to wonder why.
Please don't listen to some of the cheat-apologists on this thread.
Yes sometimes couples can come back from cheating allegedly but why would you want to? Why would you want to live on your nerves, in hypervigilence, wondering who he it texting.
I always think you can fix most things but this is now broken and can't be unbroken. You can't cellotape the pieces back together.
I promise you though eventually you will be just fine and you WILL be happy and find peace. (Not with him though)
Please look after yourself 💐