Their behavior indicates that they do indeed have something to apologize for.
It can be either conscious or unconscious, and is carried out covertly such, that the resulting emotional abuse is not overtly abusive.
If the victim does not comply, the abuser may convince the victim that he or she is in fact not good enough.
If anyone can recommend any resources that have helped them in the meantime — related to this situation — that would be wonderful.
Manipulation is a key part of gaslighting, but manipulation is a fairly common tactic, and almost anyone is capable of employing it while gaslighting, and gaslighters, are more rare.
Spend your time journaling, confiding in loved ones or speaking to a professional.