Lost, most people here are very pro marriage, even though on some days we all struggle too. That being said, if you are in a situation with physical, emotional, and substance abuse, I urge you to seek individual counseling.
Nothing excuses an affair, ever, but you can find forgiveness and a healthy relationship going forward. But you have some major life issues (forgiving yourself for A, dealing with friends and family who find out, deciding that abuse is not ok, etc), not just relationship issues, that you will have to deal with. You'll have to make a commitment to change yourself, be stronger, happier, and kinder. I wish you all the best on this journey. Divorce Busting is very helpful for stopping the anger cycle and making a decision to change things.
Faith is, at one and the same time, absolutely necessary and altogether impossible. --Stanislaw Lem
