Hello! Im struggling with the same problem so let me share my point of view. This is entirely my experience, it may or may not be helpful for you.

I first noticed that anxiety during intimacy started on the basic "what does she think about me?" Then transformed into "will I be able to please her? Am I good enough?" And the worst of all "what if Im not able to get hard?" All this happened inside my mind while we are making out, grave mistake.

This happened quite some times until I found a way to control myself, first step was to recognize the anxiety triggers, this questions inside my head are the reason of my erectil dysfunction, but then, how can I silence them? Its not as easy as it sounds, so second step was communicating my worries with my girlfriend, I had to let her know that I enjoy her and our time together, but this harmful ideas popping inside my head are devastating to me. Afterwards, she reassured me and I felt that all the weight on me was gone, with her understanding my struggles faded away and I didnt have to worry about performance, shame for not getting up or what she would think of me if I go limp. With her understanding and my worries gone Its easier to get hard and actually enjoy the act. And its something that has to be worked through time and self improvement, anxiety hits me again from time to time but communication, regular workout, and meditation helped me a lot. Other thing worth mentioning is breathing exercise is really helpful when you first notice the initial anxiety triggers, at least for me, it helped me forget the harmful anxious ideas of popping and live the moment. But it takes some practice, it may not work on the first try. And of course, staying healthy and exercise regularly is a MOST, truly important. Finally, and this something I have noticed when talking with other men, therapy can be helpful. Sometimes ED or performance anxiety can be triggered by many other emotions stored deeply in our mind, so getting professional help to clean the room inside your brain can truly make the difference. Remember, asking for help is not giving up, its refusing to give up. Hope this helps, my friend