Answer
We do not know what is meant by ?Mendeela?. If a boy and girl are engaged, they are still Ghayr Mahaarim to one another. They have to observe strict Hijaab until they marry, therefore, it is not permissible for them to communicate with one another before marriage. If by ?Mendeela? you refer to the Hijaab, then it is incorrect to remove it to please your future husband. That being the remedy to his Salaat and fasting is incorrect. What if he still does not perform Salaat and fast? and Allah Ta’ala Knows Best Mufti Ebrahim Desai