Constant guilt feeling and confusion.

I'm 19 and i really have no clue whats right or wrong in my life. I'v been with a guy for a long time and wish to spend the rest life with him but constant arguments are very disturbing and strain me mentally. And on the other hand my parents have come to know about this guy and they are completely against it which is another stress for me. By no way they r ready to accept him. Since i didnt tell them about him before, they came to know by some other ways and they are really upset with me and says that I've broken their trust and they wont ever trust me back. They keep assuming things and scolding me which is very irritating. Even if i tell them that i have not done anything ike they think they be like "you have broken our why should we believe you". I keep begging them to listen to me once, but they dont seem to be ready for that and think only what they want to think. I feel very guilty for not sharing the truth with them as soon i started dating the guy.