The counselor also told him that our marriage might stay together but he did not think so.
Did you hear this from the counselor personally or is this what your A told you the counselor said? If you heard it yourself you should address it with the counselor. If your A told you... well... A's aren't always the best sources of information.
You have to do what's right for you and your son.
You didn't Cause it, can't control it, can't cure it. Your A is the only one who can change themselves... we can only change us - one day at a time.
Have you read Co-dependant no more? If not it's worth it. Also you can find support at Al Anon meetings...
So be nice to you today!!! You deserve it.