Hi Helen, thanks for your question,
I'm sorry to hear about what you've been going through with your husband. Despite having made some mistakes in the past, it sounds like you are very committed to making positive changes and moving forward with your relationship. If the problems in the past had gone on for a long time, it may still take some time for your husband to trust that the changes that you've gone through are not just temporary. A large part of this comes from him getting to a point emotionally where he is willing to put his trust in you, and give the relationship a legitimate chance. Otherwise it sounds like you have done your part, but sometimes regardless of what you do, it is hard to change someone else's feelings until they have worked through their own personal issues and have gotten to a point emotionally where they are ready to open up again.
Although your husband may be frustrated and contemplating divorce, if he is still willing to attend marriage counseling with you, that would still be a very positive sign. Often times these changes take some time, and one of the biggest things that help is your consistency in your new positive outlook and attitude. Despite the fact that he finds it hard to trust now, the more you are able to maintain this new outlook and continue to go to counseling together, the more of a positive impression it will continue to make on him.
Right now it seems like you've done much of the work that you need to do, and are now waiting for him to get to the point where he is ready to move forward as well. Even though that may be taking longer than either of you may like, it is still likely that your marriage will improve if you each continue to make consistent efforts. If you are working through some difficult issues, then often times in the first few months of working on the relationship it can be difficult to see things improving and sometimes it actually gets harder before it gets easier. At this point though a lot of this depends on him and his willingness to continue pushing forward, and as long as he is willing to do that and you can maintain the changes that you've worked hard for, the trust should only continue to build more and more as you continue to work on this. I definitely wish you the best with all of this, and if there is anything else I can do to help please let me know.