Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.

In the Name of Allah, Most Gracious, Most Merciful.

All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.

You have deprived yourself of the blessings and benefits of the fast by indulging in activities that are sinful – sins that are wholly contrary to the spirit and purpose of fasting in Islam. The Prophet (peace be upon him) said, “Whoever does not give up speaking and acting lewdly, Allah has no need of him or her going without food or drink.” (Abu Dawud)

Therefore, I would urge you to repent and make up for the fast thus nullified. Even if from a purely legalistic point of view, it is valid, there is no spiritual benefit from it; therefore, you may do well to make up for it – after having repented of your sins.

Allah Almighty knows best.