He is bordering on unfaithfulness, though he may not have acted it out. You need to go to your pastor and/or a counselor even if he doesn’t come with you.
He is very secretive about her and doesn’t let me see what she writes to him.
My husband gets very angry when I tell him how much this hurts me.
How can you be united as a couple if another woman is so important to him that he ignores your concerns and talks to her daily and keeps it secret from you?
If these relationships are not intimate or sexual than he should be able to show you all the emails he has sent and received to disprove any suspicions you have.
A year ago my husband started chatting with women on the Internet. He says that the women don’t mean anything to him but he won’t quit.