Especially when it's someone you can't cut ties with.

There's no road map...it just takes time.
I've found that people who do foul shit despite you telling them how it feels either don't care or can't help it. If it's blood and you can't cut ties...something has to change..business as usual is unhealthy.
Only you can decide that change...it cld be lowering/removing all expectations of that person or changing the level of contact you have...something.

But it takes time man...you can't rush it...and don't buy that bullshit people sell these days about having to have to forgive this minutE and feeling rage etc is weakness / lack of control..
Do you, take your time and be gentle with self