In the moment? I usually say, "my anxiety is really bad right now, I need a few minutes to calm down" and remove myself from the situation. After, I consider what it was that made me anxious (maybe write it down in a journal) and then communicate to my partner that it triggered my anxiety. Usually, we'll have a discussion and decide that either (A) my partner avoids doing the thing/creating the stimulus that triggered my anxiety (B) I find (healthy) ways to cope with the anxiety or (C) We agree that I can remove myself from the situation when the stimulus triggers anxiety

Thanks Raz. In this case it was a trigger that reminded me of an ex, and I have this terrible fear that my brain is going to associate my new amazing partner with the bad things of my ex.

The association would be with the stimulus, not necessarily your partner. Two people can do the same thing and be remarkably different people. Over time, your association with the stimulus might become positive, reminding you of your new partner more often than your ex

Thanks. It’s been quite a while now and it’s been flaring up in the past week actually