Hi, Hopefulguy, welcome to SI.
I am going to bump up a couple of excellent resources for newbies (in this forum), one entitled Tactical Primer, the other Before You Say Reconcile.
A couple of things are jumping out at me....is she still working with OM? She needs to go NC (no contact) immediately with OM. She may also have to consider finding a new job. It is going to be extremely difficult for any reconcilation if she still has any type of communication with him. Is he married?
Also, has she given you access to her cell phone bills, email accounts, facebook, voicemails, work emails? She needs to be completely transparent. Accountability for her whereabouts at all times.
Your emotions are going to be all over the place. Forgiveness is something that needs to be earned. Reconciliation is a gift.
Infidelity causes the crazy train, sadness, numbness, anger, rage, disgust. You will feel all of the above, trust me.
What was it that made her confess? Was it true remorse or was someone going to expose the affair?
Please get tested for STDs (both of you). Also, it is a good idea for the both of you to begin counseling, I support individual counseling first as she has to get to the bottom of why she allowed herself to travel down this destructive path.
Never accept blame for her actions. Ever. She had other options, communication, counseling, separation.
Post often and read, read, read, in all forums if possible.
Lean on a TRUSTED family member or friend, lean on us. We have walked in those painful shoes, unfortunately hope for the best but prepare for the worst as this is a long, long journey.
((((Hugs)))))