How do I keep my anxious thoughts from ruining a relationship?

Hello, I wish to applaud your courage in reaching out to a stranger to ask a vulnerable and possibly tough question. That said, I am sorry to hear that your partner seems to be experiencing anxiety and is feeling overwhelmed. When your partner 'goes quiet,' I can only imagine that you must feel left out, disconnected, and perhaps a bit isolated. You did not mention how you have tried to cope or address this with your partner? I assume that you have tried to communicate with your partner? If so, I wonder what your outcomes have been so far when you have tried to reach out. I also wonder why you are writing on behalf of your partner when your partner needs to step up and take responsibility for their own mental health issues. You cannot fix them. We cannot fix another person, ever. My humble perspective. Have you considered that anxiety is just a fancy word for fear, so if your partner is feeling anxiety, their best way forward would likely be for them to reach out to a professional counselor or psychiatrist to explore what is the origins of their anxieties in the first place so that they can reduce that anxiety by getting to the true roots of it? There are of course daily coping tips for anxiety that your partner can try, such as meditation and relaxation and positive thinking approaches, but doing that deeper work for them to really explore the real roots of that anxiety would likely yield them the deepest long-lasting benefit for a more healthy life emotionally. When you ask about keeping their anxious thoughts from destroying the relationship, I am assuming you mean your partner's thoughts. Again, you cannot change another person. You can only work on yourself and suggest to them that they do the same, work on themselves by seeking professional assistance and therapy. This tendency of your partner's that you describe briefly here does not sound emotionally healthy and it surely does not sound as if it supports having a healthy relationship. Working on yourselves as individuals first can be a real jumpstart forward to you both. I wish you well.