downhub, oh man, I am really sorry to read this. I am sure you do feel (today) that things are passed saving. Things are quickly spiraling out of control, and that is especially hard to handle with a broken heart! I just want to tell you to try and not think too far ahead. Your sitch is still very early. Some of us are several years ahead of you (some even more) and we can tell you first hand that people do change (for better, for worse, and sometimes back and forth). You are just in the thick of the hard part right now.
Sara brought up a well documented phenomena that most people don't know about. I had someone close to me that is very involved in her adoption support groups and knows several people that have rekindled relationships with family in adult years, that quickly turned to romance. I know it's hard to understand and she continues to call him her "uncle." Honestly though, everything you are describing IS the definition of an affair (if it's not already a PA it will be soon). Unfortunately, as you are learning, you really can't control her. The more you can step away and go dark, the better.
Please, please take Sandi's and Sara's advice. I am concerned that she is trying to manipulate you and trying to gather evidence against you. Give her nothing and don't take her bait. Don't initiate any contact at all, unless you have to communicate about your son. I wouldn't even speak with her in person or on the phone right now if you can avoid it. Simply email in a very concise and respectful tone about exchanging your son and his needs only. Do simple and kind exchanges with her and then leave as fast as you can. This also keeps her wondering and she loses control over you.
Getting legal advice can be scary and feel closer to the end. This is really not the case. If you can separate your legal/financial situation from your emotions right now, that is key. You don't have to retain a L or start any action. Simply get some advice and empower yourself and know your rights. There are many good family practice lawyers that will give you a free consultation. Try and see a couple and go in with all of your specific questions written down. I never got D, but am so glad I had done this and knew where I stood.
Lastly, I hope you are getting some support for yourself. If you can, find an IC for yourself. Lean on your trusted people right now. Make some fun plans to get your mind off of this. It's very stressful and painful when this happens. I know there is a very big family, and you are close to her family, I would be careful not to share any details with them. It will only make things more complicated and her family (as crazy as it sounds) may take her side. These sitches get ugly fast. In terms of OMs W? Well if she doesn't already know, she will VERY SOON. My guess, is she will not tolerate this much longer. So take a step back and remove yourself from all of them. Your W doesn't deserve to know what you feel and think right now, and the less she does, the less she can try and blame you.
Hang in there buddy. Blu
“Forgiveness liberates the soul. It removes fear. That is why it is such a powerful weapon.” – Nelson Mandela
