Hello yellowdoxie. Welcome to the greatest club that no one ever wanted to join.
Read the "Tactical Primer" pinned to the top of the JFO Forum. Also, the newbies thread.
In the pop down menu at the top of the page you'll find a link to The Healing Library. Inside the "Articles" tab you'll find a wealth of excellent essays written by veteran SI members. These essays are a great place to start your journey of recovery and healing.
Please understand that the majority of WS (wayward spouses) will lie, blame-shift, deflect, obfuscate, minimize and attempt to justify their adultery. Like anyone else busted for wrong doing, they will go straight into "damage control" mode. Be prepared for any combination of this nonsense.
For most people, the betrayal of infidelity is a profound shock and a severe emotional and psychological trauma. For a while you're going to experience a shitstorm of emotions, thoughts and anxiety. Know that this is a completely normal reaction. You can mitigate the effects by consciously doing your best to take care of yourself.
Stay hydrated. Dink lots of water.
Avoid alcohol and rec drugs. They will only prolong the suffering.
"Hit the gym." I know it's a cliche, but the endorphins and hormones will help.
Consult your PCP and let him/her know what's going on with you. Most likely they've heard it before.
For months after d-day (discovery day), I couldn't function. I lost over 30lbs in less than three months, couldn't sleep, couldn't concentrate, remember shit, and experienced a roller-coaster of emotions. It was all perfectly normal.
Do not start marriage counseling. Not yet. At some point in the future, if reconciliation is a possibility, marriage counseling might help. Individual counseling for both of you is the way to go.
I know this is difficult, brother. It's the most painful and challenging shit I've ever experienced. Know that you will recover and heal. It takes time and a little self care, and it's a long journey, but you will get there.
Keep reading and posting here. This wonderful little community of ours saved my sanity. There is tremendous wisdom to be found here.