Okay, so try to calm yourself so that you don't act out of panicked emotions.
Have you read Divorce Remedy? It's important that you do.
Instead of focusing on the OM, look deep within yourself and evaluate how you've been as a H. Many times, a woman will turn to another man when she feels lonely and her emotional needs are not being met. After years of living with unmet EN, It causes her to be vulnerable to a man who gives her the right kind of attention. So she's probably not in love with this man, but he makes her feel special. The more you try to attack him, the more she will defend him. He is really a byproduct of the problem that was already there in the MR.
Go to work on yourself......fast! Pull back and put no pressure on her by talking about the MR, OM, A, the future, how she feels, what she's going to do, telling her you love her, etc. Don't smother her with your presence, following her around, making contacts throughout the day. There is much more, but start with these.
Set goals for yourself. Not about her, just you. Write them out here. What can you do to find that man you were before M?
Get a life that does not include your W. Make yourself leave the house and find something to do. Buy some new clothes to fit after losing the weight. Make sure you look clean whenever she sees you.
Polish up your personality, manners, & charm. Break old habits that put you in a negative light or turn people off. Don't behave like a jerk. Regain your manly confidence and be a strong leader for your family.
During your soul searching, decide what you cannot live without.....and what you absolutely won't tolerate in you life. This is not to control anyone else. It is to protect you. Those will be your boundaries.
Others will come to help you. But you have to get this foundation before you start making some kind of big move. Those big moves can really make things much worse.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!