I agree with you. It's really hard on us and on the other children when we have a screamer. I just really hate interviewing and transitioning so I'd rather keep going and get it over with, rather than start over from scratch. But sometimes you just know you have to cut the ties. I respect you for that completely. You have to know when you have reached your limit.
momof4 is right. Only you know what you can tolerate and only you know how stressful it is on the little one. Just make sure you're communicating honestly with the parent so if termination is in the future it's not a total shock. Sometimes it just does'nt work out.