It didn’t happen ‘because’ you trusted – it happened because your husband has an addiction that he neither wanted nor asked for any more than you. Yes we trust because until something happens to break trust that is what we do when we love someone.
Don’t let his addiction spoil your happy memories; don’t let it take away that which was possibly true. He smiled because he wanted to feel and be ‘normal’, not everything is a deceit.
I am sorry that I broke into a time when you were trying to be happy and reminded you of that which you wish to forget. There will come a time when you can forget and be the person you want to be without effort, if it wasn’t so I wouldn’t be here. It is my belief we can bury the problem but at some time, if we want to be forever free, we have to face it. You were still looking at this forum for you to be able to see my posts which says you are still looking for ‘your’ answer and you are not burying the problem. Keep talking, keep learning, the more knowledge you acquire the more ready you will be to make ‘your’ informed decision, the one that you will ultimately be happy with.
To be able to live in the moment is a gift that is even more precious for having lived through a bad experience. You already know the things you want to appreciate and you can make them happen. Spend time watching those leaves fall; make a point of enjoying your children, don’t let them be a grind. Nothing is too late.