You have two options, leave him or leave them. Your life events, upbringing, emotional attachments etc will play major role in your decision. You have almost decided to elope. This is surely going to shock them and they will be shaken mentally as well as socially. However, if you are thinking of fleeing and expecting them to react in a way you think is little too much on them. Honestly, this you should have thought while getting in to relationship and taking it to deeper. Now you are at the stage where you cannot expect roses all the way.