Praise be to Allaah.
You have to ask Allaah for forgiveness and repent to Him for
what you have done, and you have to resolve never to go back to that. The
fact that you touched this woman does not mean that you are obliged to marry
her; there is nothing in Islam that compels a sane adult to marry any woman
whom he does not want to marry. No marriage is valid unless it meets the
necessary conditions, one of which is the consent of the husband who is
You do not have to tell your parents or the girl you are
going to marry about what happened; rather you are obliged to conceal what
you have done, and to repent, and this is between you and your Lord. The
Prophet (peace and blessings of Allaah be upon him) said: “Avoid this
filth that Allaah has forbidden. Whoever does any such thing, then let him
conceal it with the concealment of Allaah.” (Narrated by al-Bayhaqi; classed
as saheeh by al-Albaani in al-Silsilah al-Saheehah, no. 663).
“Filth” means evil actions and bad speech that Allaah has
forbidden. Subul al-Salaam, 3/31
And Allaah knows best.