Hi petal.
Unfortunately he never changed, he was a cheat when you met him, he kept being a cheat with you. All red flags were there, you only wanted to believe that he could have a true connection with you and would not abuse and hurt you.
But he did.
There’s one thing, once a heater always a cheater, is not quite true in the sense that a person can’t change (they can, profoundly), but it is true in the sense that you will never be able to force change upon the,.
They can kill the cheater and become the human version of themselves deserving love and trust.
But it must start from within.
Any outside support will always fail unless there is a primal drive coming from the wayward towards growing up and becoming whole.
Staying broken is easier, performing is soothing.
They can feed their validation both through acting in secrecy and by superficial compliance that gets praised or encourage.
But there is not truth unless is coming from within.