parent forbid the relationship of mine and my bf

For the first time when my parent knew we were together, almost everyday we argued about this. And almost causing me not going to university. So, we broke up. The we never contacted each other almost a year. But i also dont know why, but suddenly we just got back together till now.  He also already know that we cant be together forever, but we just cant let each other go, esp. myself (this is really heart breaking). 

But suddenly my parent brought this matter up again, and they were asking me to let him go step by step. But i just cant.

I dont know what i should do right now. I mean, he is my first love (really! Im not talking like a fairytale princess, but really, Im 22yo, and he is also my one and only bf till now). 

So, can someone really tell me what i should do? Because i really dont know what i should do.