Girlfriend Ranting

My best and oldest friend frequently does not agree with me about things large and small. We are part of three couples who have been friends for many years. When we have disagreements, she will not agree to disagree. When this happens, she refuses to talk any more, remaining angry and pouts the remainder of time together. We do not live close to each other so our main means of communication is a monthly phone call that I initiated as a way to remain in touch. She is currently angry with me over a visit I plan to make with the other couple. On our last two monthly phone calls she answers my inquiries in “Yes” or “No” responses only. I am tired of this childish behavior but know that when I attempt to address this with her, additional ranting will ensue. I don’t want to cause irreparable damage to a valued relationship involving the six of us. Thank you.