I will not lecture you about God's comparison and mercy, as you must be well aware of how the Almighty forgives all sins, and cleans our slates once we turn to Him with sincere repentance.
It is forgetting the past that you must be focusing on, and how you are able to develop a level of piety that you will enter into a new phase in your life, based on religious devotion and spiritual growth. That will not just ensure you've been forgiven, but also keep you on the straight path.
Your sin is between you and Allah ta'ala, and you must not reveal it to anybody. From a shar'i perspective, you do not need to tell your future spouse your previous sin.
Once you have changed your ways and sincerely forgiven, and became more religiously active and aware, then you live your life normally, and think positively for the future, not allowing the past to define who you are.
With prayers for your success.