Assalamoalaikum,
الجواب وبالله التوفيق
When an adult and sane male and female, in the presence of two adult and sane Muslim men as their witnesses, perform their Nikah, then from a Shar‘ai standpoint, this Nikah is considered officiated. However, there are other etiquettes and conditions for a Nikah, and announcing one’s Nikah openly is one of those conditions. As a result of fulfilling this condition, people in general are informed that this relationship is a result of the Nikah, otherwise there is possibility of it leading to distrust and leading others astray. The action of hiding Nikah is against the outlook of Islam as it is a source of many evils and adulterations. Therefore, the Islamic Shari‘ah has depreciated secrecy in performing Nikah. Try to resolve the family issues and use restrain and be patient until then.
Your statement regarding “any more time like this will lead us to commit zina”, the possibility of that happening is because of the fact that you must have been maintaining some type of contact with your fiancé and as a result of further delay you will get involved (nauzubillah) in such a heinous crime. May Allah Subhanahu Wa Ta‘ala protect you. Nonetheless, you should understand the fact that just due to an engagement, it is incorrect for you to keep any relation or any type of contact until the Nikah is performed. The woman is considered a stranger for the man until the Nikah is performed, and subsequently the rulings applicable to a woman who is a stranger become applicable in your situation as well. Just because a woman is someone’s fiancé, being in contact with him does not become correct.
Therefore, be careful and cautious regarding this issue, InshahAllah, you will remain safe from the acts you are fearing and anticipating. In addition, try to convince your families and elders for performing your Nikah as soon as possible.
عن عائشہ ؓقالت قال رسول اللہ صلی اللہ علیہ وسلم اعلنوا النکاح واجعلوہ فی المساجد الخ
(کتاب النوازل ،ص 62، ج8 بحوالہ سنن ترمذی)
(عن نافع مولی ابن عمر یقول لیس فی الاسلام نکاح السِّر(کتاب النوازل ص 63، ج8 بحوالہ مصنف لابن ابی شیبۃ
واللہ اعلم بالصواب