All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
We appreciate your desire to follow Islam and to avoid any deed that contradicts Islam. May Allaah bless you and protect your from sins.
As you know, any kind of personal relations (even talking) with marriageable man without necessity is forbidden in Islam. So, you have to cut all contacts with this man. See Fatwa 84281.
We advise you to endeavor to convince your parents to marry you off since the studies do not contradict with marriage. But, marriage is more important than studies if one fears seduction or committing illegal sexual intercourse. See Fatwa 84534 about marriage during studies and Fatwa 90554 about the ruling of marriage if one fears temptation and Fatwa 82130 about how to convince the parents to accept the proposal of a pious man who proposed to their girl. If your father insists not to marry you off to that man you have to obey him and be patient read Fatwa 89974.
Allaah Knows best.