One of the realities in contemporary society is that many couples come to marriage with previous sexual experience, either with each other, or with other partners. The commonly held idea is that sexual experience before marriage better prepares you for marriage. All of the research indicates otherwise. In fact, the divorce rate is twice as high among those who have been sexually active before marriage.
The Christian answer is the confession of wrongdoing and genuinely forgiving each other for past failures. The scars of the past may remain, but the scars serve as a reminder of the grace and love of God. When God forgives us, He no longer holds it against us. We in turn, forgive each other.