Golden Heart, you say that you're torn between two. From what I understand, JD hasn't been in contact with you since he left. Is this correct? If so, what gives you the impression that returning to JD is an option?
As far as Grant goes, if he's not meeting your needs - treating you badly and flirting online - why are you still with him? You know you can simply dump him don't you.
The issues with your parents don't make much sense without context. Do they know that JD ended the relationship and has had no contact with you? Why do they dislike Grant? Is it because Grant has been unpleasant to them or because you've been telling them that you're unhappy with Grant? How old are you and why were you living at home?
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.