Right now, you're really suffering, and it feels like you're in the dark with no way out. It is said that the days of not being able to sleep without appetite continue, so please take care of yourself that your mind and body are in a state close to the limit.
You blame yourself for being “terrible,” but the reason you think so is because you are inherently sincere and have a heart that cares about your husband.
I will sort out the current situation and tell you points of view to lighten your mind even a little.
① “Talking” and “not talking”
Sometimes speaking honestly isn't necessarily “sincere.”
The risk of speaking. Your sense of guilt may be lightened, but it will cause your husband to inflict two major wounds at the same time: “past betrayal” and “humiliation that the neighborhood knows about it.”
Choosing not to talk. It is extremely painful, and it is also a cruel act of kindness to protect my husband's current happiness, which requires preparation to “take it to the grave.”
② Using “husband's happiness” as the subject
My husband says, “I'm happy right now.” This is an irreplaceable truth.
If you confide in it, that “current happiness” will collapse in an instant, and there is a possibility that all memories will fade by going back to the past.
Is happiness for the husband “knowing the truth and getting hurt properly,” or “living a peaceful everyday life without changing from his beloved wife.”
③ How to deal with neighbors
Neighbors don't talk to their husbands is a kind of “consideration.”
Rumors gradually fade as new topics come up. It's probably more like a needle right now, but if you get upset here and change your attitude or go around suddenly apologizing, it will only make the fuss louder and increase the risk of getting overheard by your husband.
④ WHAT YOU CAN DO
Right now, don't rush to the conclusion of “whether or not to divorce” or “whether to confide.” Judgments when the mind and body are weakened inevitably tend to go in an extreme direction (in the direction of self-punishment).
First, get back in shape. Rest your body while drinking a warm drink.
I will do my best to support my current husband. You can't change the past, but how happy you can make your husband in the future depends on how you behave.
Also, consider spitting out all of your chest to a counselor or someone who has a duty of confidentiality, such as consulting with a trusted third party (expert).