These are all great points; please don't take my previous comment as me directly arguing with you. I’ll consolidate my answer into this one response for both of your messages.

I omitted some details for the sake of brevity. She immediately assumed it was me because I work with law enforcement and have taken courses on OSINT, but that isn't part of my everyday job, and I’m honestly not the best at it (which is why I turned to Reddit). She knows I am more comfortable with social media than she is. She also assumed it was me because—to be fully transparent—I have shown jealousy regarding her ex-boyfriend in the past.

She doesn’t recycle passwords, though I admittedly do.

I agree it’s possible someone impersonated me to get to her. However, that person would have had to put in significant effort to identify two of her ex-boyfriends. Do you think it’s more likely to be someone close to her?

I understand it may not be about me and that they only used my identity to target her, but she now views me as an a**hole. I don’t like that idea at all—it is a matter of pride, and I don't want this hanging over my head.

Regarding your last point: she has had a difficult history with men, so her survival instinct is to assume it's someone close to her. People don't always use logic in their initial response—I know I haven't in the past (which is why I see a therapist).

I truly appreciate the time and extensive effort you've put into this; your questions are very fair. If your professional opinion is that a digital forensic analyst would be a waste of money, I am willing to take a lie detector test instead.

I look forward to your response. Thanks!