If you cannot keep up healthy boundaries with that person, if that person has really hurt you or done something that is genuinely abhorrent or terrible in no way, should you feel obligated? Cut them off, get them out of your life. I think the other thing is when do you know that you are ready to date again? I don't think you ever know. You will just come a point where you will just realize that that is actually an option now and that you are in the right place to be able to meet someone new.