Will God forgive my sin, and will He turn to me in mercy, and will people forget what I did after I committed a shameful act with the help of my husband, which led to my disgrace and everyone shunning me?

It is not permissible for a woman to address a non-mahram man in a submissive or lustful manner, due to the Almighty's saying: "Then do not be soft in speech, lest he in whose heart is a disease should covet," nor is it permissible for her to be alone with him or go out with him without a mahram. The husband's approval of his wife doing so indicates the weakness of his faith. The questioner must offer sincere repentance for what she has committed, for whoever repents with true sincerity, Allah will accept their repentance and forgive their sin.