Your spouse cannot "bad mouth" you and cause you to lose custody of the children. Generally, he will have to prove that you are a danger to them mentally or physically, or that you are unable to care for them properly AND that he is more capable of doing so. I know that I let my fear of losing my son keep me from going to a psychiatrist for several years, but once I finally went, I felt SO RELIEVED! My pdoc promises that while I have diagnosed problems, he would testify to my parenting ability if this should ever arise as a problem.

So, no, going to therapy cannot be used against you. Mistreatment is going to be the "big" deciding factor in keeping or losing children.

Also, I'm not sure it is legal to use your journals against you. Does he have any way to prove they are yours?

I hope this goes ok for you.