How do I know when to leave?

I have forgiven, I have been drip fed bits of information reluctantly by my husband. I have also experienced an inability for him to be open and honest. I have told him repeatedly if we are to rebuild I need honesty and openness, and loyalty when our couple is challenged by outsiders. He continues to break promises and let me down. I love him dearly but I’ve been through hell, I’ve suffered without support or only fleetingly glimpses of support. It’s so hard to let go when I’ve loved him so much, but he just can’t come through with what I believe is fundamental to our relationship. I feel like I’m cutting off from myself but I also feel like I need to save myself. This hurts so much and is so confusing.