Ok, thanks Joan,
It is very natural to feel sad about your marriage. This is a loss and as with any loss, you need to mourn. You have been betrayed, deeply hurt and your trust in your relationship was taken away. It is ok to feel as you do.
Part of the problem here is that you have to be reminded of your pain each time you see your husband and hear from him or hear of him. Your wound is opened and everything is exposed, leaving you to start back at the beginning with how you feel.
Since your husband is not interested in addressing the problems in the marriage and he has essentially cheated on you by living with this other woman, it may be time for you to consider moving on. That means divorcing him and dividing up whatever property you can, whether that means paying him for his part of the house or selling it outright and splitting the profits. You may want to consider doing the same with your business.
Emotionally, it means no longer seeing your husband or having anything to do with him. If someone tries to talk with you about him, you have to establish boundaries with them by saying that is not something I want to talk about anymore.
This is not going to be easy. There is always a desire to hold on and see if things change. Letting go is very difficult, especially after so many years together and sharing your life and your children. Making that choice can add to your pain, a way of resigning yourself to the reality of the situation. But without making a choice, you allow him to control you and your life. And he is not the one who is hurting. So he will continue to do things that hurt you as long as he is allowed to.
By taking back control of your life, you can heal. Start by learning all you can about divorce and loss. Here are some resources to help you:
How to Survive the Loss of a Love by Peter McXXXXX, XXXXX H. Bloomfield and Melba Colgrove
Rebuilding: When Your Relationship Ends, 3rd Edition (Rebuilding Books; For Divorce and Beyond) by Bruce Fisher
Getting Past Your Breakup: How to Turn a Devastating Loss into the Best Thing That Ever Happened to You by Susan J. Elliott
Should I Stay or Should I Go?: A Guide to Knowing if Your Relationship Can--and Should--be Saved by Lundy Bancroft and JAC Patrissi
You can find these books on Amazon.com or your local library may have them for you.
Also, consider seeing a counselor on your own. Talk with your doctor about a referral or search on line at http://therapists.psychologytoday.com/rms/.
Support groups on line or in person can also be a big help. Here is a resource to help:
Most of all, know that you will get through this. Take one day at a time and do what you can. There is no perfect on this, only what you can do.
I hope this has helped you,