1) yiu should call off your engagement before you marry your boy friend
2) courtesy demands that you inform your fiancée that you love another man and want to marry him
3) yiu can then marry your boy friend
4) since you are adult you are free to take your own decisions
5) if your parents file any kidnapping case against your boy friend you should inform the police that you married your boy friend as per your own free will
6) you can also lodge complaint with state commission of women that you are being forced to marry against your wishes