Mona, If you aren't sure you are ready to toss in the towel, then sit quietly and do nothing. The answers will come. However, there is no need to poke the bear, especially when you are angry yourself. Take the high road as often as you can. Don't lower yourself to his level any more than you need to.
I don't think you've been wrong about the man you married for 20 years, but people change, especially when they are having affairs. He's changed into someone you hardly know right now and that person is not someone you want to be around unless it's dealing w/your children's activities.
I'm worried about you and I sense the hurt and disappointment in your postings. Mona, you've come a long way since you posted a few years back. try not to go backwards, but forwards. You are a beautiful woman who has a heart of gold and want to share it w/someone worthy of your love.
Right now, lashing out, trying to have discussions w/him are fruitless. Why? Because he's tuning you out more often than not. He figures he's separated from you and doesn't have to listen to you venting or just speaking. I'm going to suggest that you try something different. Instead of lashing out at him,try speaking to him in a very calm, concise manner. Keep the conversation short and sweet. The shorter you keep it, the better he'll comprehend what you are saying.
Also, one last word of caution, if you do end up w/someone and you have relations w/that person, be sure you are protected. You just never know in today's society what is being passed around and I would hate to see anyone receive the gift that keeps on giving. (I know you already know this...but I always try to remind posters.)