Hi Kylin, and welcome to the forum and our TMS community.
Here's my take on this. Part of what TMS does is that it weakens your immune system, especially when you are dealing with what we call "TMS equivalents". In that sense, we have gone far beyond Dr. Sarno's original theory of oxygen deprivation and muscle pain, and Dr. Sarno himself, as he was approaching retirement, was starting to veer away from "pure" TMS - he starting talking about the equivalents, and I believe that he even suggested that rather than Tension Myositis Syndrome" TMS should stand for "The Mindbody Syndrome".
So when you think of TMS as covering all Mindbody conditions, you have to look at the established fact that the long-term stress of emotional repression will cause actual physiological changes to your body. Everyone knows this! Even the most traditional doctors will say that stress is not healthy for us.
As someone who suffered from probably dozens of different TMS-caused conditions off and on all my life - all starting at a very very young age along with chronic anxiety, I can look back on my early struggles with UTIs and say without a doubt that they were caused by my condition of constant stress and anxiety - including, probably, my ambivalence about intimacy - emotional as well as physical (thanks, mom).
You can attack this in several different ways. You're already well on your way to working on accepting a TMS diagnosis, which is the vital first step.
Now, I want to assure you that by the time you have a measurable UTI or yeast infection, you certainly have a physiological condition which I'm pretty darn sure should be treated. That means that the key for you is to change your mind about your inability to avoid infections, BEFORE the point at which an infection has to be treated. You need to know, and accept, that you DO have the power to change this.
1. Be sure that you've cleaned up your diet, first of all, and that you are drinking plenty of plain old water (preferably filtered from your tap, not bottled). Knowing that your diet and drinking habits are conducive to good urinary health will help your brain to visualize staying healthy. If you're ingesting too much sugar or sugar substitutes (which have the same effect on your metabolism), you know that's not healthy, and your unconscious brain knows it too. This is an important point, and one I recommend that you take seriously!
Visualization is a powerful tool for your immune system, and it makes sense to use common tools to help you visualize a healthy immune system. Every time I take Vitamin C, this is what I'm doing. It's just a tool - your brain is doing the real work, because it's in charge of your physiological processes, including your immune system.
2. Engage in a program of mindfulness in which you learn to recognize the multiple times that your brain creates worry that you might have an infection. Once you pay attention to this you'll be amazed at how ubiquitous (and damaging) these messages are! Learn to hear the negative worry messages, and then learn to squash them! You can counteract them with constructive positive messages. To use my personal favorite, the one I use all the time - in your case it could be "Hey, this is NOT necessary! A UTI is NOT inevitable, my body is perfectly healthy, and my immune system can fight any stupid bacteria or yeast that try to get in, and it will!" As you do this, take a few deep breaths, drink a glass of plain water, maybe take a Vitamin C tab along with the water, and visualize your body fighting off the infection. Repeat the verbal affirmation and the deep breaths as often as necessary - you can't overdo that part. Don't overdo the water, but do make an effort to drink extra, and definitely don't overdo the Vitamin C, because that's not really necessary - taking it once when you think you're at risk of getting an infection is just a tool to boost your visualization.
3. If anxiety is any way, shape or form a part of your life, you need to get a handle on it. I highly recommend Hope & Help For Your Nerves, by Dr. Claire Weekes. This little book was the second book that changed and saved my life back in 2011 (the first one being The Divided Mind by Dr. Sarno).
Good luck, and keep us posted!
~Jan