let down

I was recently let down by someone close to me. Someone I should be able to count on. To trust. And the worst part is it's not the first time. And I'm certain it won't be the last. Breaks my heart. How can I keep trusting? How can I keep putting my self out there? You know the saying "fool me once, shame on you; fool me twice, shame on me" well that's where I am right now. sick and tired of dealing with the drama....the disappointment and while I know it's not very Christian of me....I just want to be done. Is that wrong? Am I a terrible person for giving up? I can't fix the situation. I've tried for years...literally years. And while I love this person dearly....more than words can explain. The pain that this person causes me is now affecting my children. And I CAN'T have that.