I've seen two main variations of these kinds of posts - one variation is something like this, where the OP has a history of cheating and dishonesty about their sexual past which their partner is understandably upset about, and then the second variation is really heartbreaking. The second variation is when the poster has a past history of experiencing sexual abuse and rape, and their partner is upset that "other people got a chance to be with them first." I recall one post maybe a few months ago where the poster's partner found out she had been gang-raped years prior and he was angry because "she didn't tell him she was promiscuous" and basically "multiple men had gotten a chance to 'enjoy her' before he did."

I think context is always, always key and her edit and comments give much more context than the brief summary she initially provided.