I don't know about hiding those sort of things from your husband. But in this day and age, the way guys treat girls with a past, even though they may have had a past, I can understand why girls keep their mouths shut.
Mistakes you've made in the past are to be shared with your partner, so you both can learn and move on. That's not easy to do for everyone, I guess.
Everyone has make his/her own decisions.
But Islamically telling you that, if one committed a sin and he/she repented it is also forbidden to share with others. All have to do quietly seek Allah fogginess and mercy.
Allah is kind and mercyfull, and he is also Sattar (the one who hides).