There comes a time in life when you know you need to walk away. Whatever the situation is, you just know it.
I'm a born optimist. One of my MOs is to always assume best intent. In whatever someone does. Even if they do something hurtful or isn't there for you. Always assume best intent. But when they consistently seem to let you down, there comes a time when even the biggest optimist has to say "Enough is enough. I am done letting you drain me."