There is no finite answer to your question – we all react in different ways but I will give you my thoughts on it.
In my opinion, healing must come first and in the same way that healing has to be selfish for the CG so it has to be for those who love the CG because neither can heal the other. Unless we heal I don’t think we can forgive, trust, rebuild or share – it would be like walking on thin, cracked ice without any hope of gaining solid ground.
I suppose that constructing the new way or determining the new relationship comes next. When I was in Gamanon I heard outcomes from the addiction that I had not expected. We had husbands/wives and partners in my group and down the corridor were the respective husband/wives and partners in the GA meeting. Some were adamant that forgiveness was never going to occur because they had done nothing wrong (which indeed they had not. Through no fault of their own they had found the addiction to gamble forced on them and were determined that blame for it lay solely with the CG. My firm belief is that a CG could/would never want or ask for this horrific addiction, anymore than those who love them, so to my mind when a CG has the courage to control his/her addiction they deserve support, not blame. I was fortunate that the lady who led my meetings was married to a CG who was 12 years into his gamble-free life and that was 10 years ago. (He is still gamble-free and a remarkable man). She helped me heal and accept that although I had done nothing wrong, I could not have known how to do that which was right for my loved one weighed down with a secretive, divisive, destructive addiction.
So with healing I believe that discussion on constructing the way forward can take place.
I believe that true forgiveness can only come with understanding and depends on the individuals involved. For some it can come before healing but for me it took a very long time. I remember being surprised by it and subsequently liberated by it.
Trust is the most difficult of all. Year of deception, countless lies, manipulations of situations when you felt you were in control of your life and you were not, all add up to a terrible loss of trust. Knowledge helps to understand the lies and deceptions but it is my belief that retaking control of your own life is one of the major properties of healing and the thing that carries you through to safety.
I can only tell you that I did regain trust and hope that some of the above answers some of your questions.