Gaslighting is when they repeatedly trigger your nervous system and damage your mental health. They blame you when you react to their manipulative behaviour, but will never accept accountability, or discuss their disrespect.
Please don't spend your time trying to make sense to people who keep hurting you. Their behavior doesn't make sense. Their lack of remorse doesn't make sense. Their assumption that they can treat you poorly & still have a permanent place in your life, does not make sense.