Infidelity Support Group
Any relationship in which one partner engages willfully in sexual relations with another outside of the partnership is considered to have experienced infidelity. This breach of trust is often traumatizing for the faithful partner as well as the relationship, and support is often needed to heal emotionally and to decide whether or not the relationship should continue after...

Writing it out can help... can you tell us what happened?
Did you find out or did he tell you?
How long are you two married, kids?
What is the cheating?
We're here for you! You're not alone. You WILL get through this.
It is normal to feel how you are feeling, and it sucks. It really does. But, his cheating behavior seems pretty clear and repeated. It is hard, but you are in a position of reassessing yourself and your relationship with him. What helps is taking a review of yourself and figuring out what YOU need and what YOU want.
You did nothing wrong in this relationship. This was all his CHOICE. There was nothing you could have done better, or differently, or anything else you could have done to stop this. This is all on - him, You are the victim in all of this. Do not believe anything he says... why would you... he is a liar and a cheater! So, don't believe anything he is trying to say about YOU.
How long are you two married? Do you have kids?
Can you get a therapist? You could look online and start therapy, call around to some therapists, you may even be able to start therapy today.
Think about what you want to do. If you want to divorce or separate. Do you have friends or family you can talk to? Talking, and also writing things out (such as in a journal), will help you to get your feelings out and to start making a plan of what you are going to do next.
You are in charge! You decide what is best for YOUR life. Don't listen to any of the crap he is trying to tell you about you. That is so low of him to even go there, especially after what HE did. You make your own decisions. You are your own person. A strong woman with a mind of your own. You are strong and a good, worthwhile person.
When people tell you it's not you it's him, they're right. Go easy on yourself. If you can get away from him, do so. The best thing for me has been that we've been in separate states since I found out. It gave me time to process a lot of $hit.
Take care of yourself.
Second....... it's not your fault
Things that I wish I had done was a month of no contact. Whether you leave or he leave.... You need time to think without him constantly in your face manipulating you.
My CS came clean... eventually.