DD has a built-in vulnerability that I'm not sure she CAN eliminate without changing who she is-- she wanted a real connection with a true peer. She wanted it so badly that she was willing to ignore red flags, and the abuser was pretty savvy about her weaknesses (having studied her at some length prior to engaging with her). So what is the answer?
One answer is to learn the tells to when you should start thinking about red flags.
And if you see a red flag, you should *think* about it and not ignore it.
So, if you learn the tells/red flags, then you can still be open...but if you see one..and then two...and then three...well, then you should start watching things carefully.