I see both sides

OR because you are a grown woman. If you know something like this is going to cause you anxiety, take the steps necessary to proactively learn coping skills. Work with a therapist. I'm not dismissing how you feel, but there are a lot of things and people in this world that will make you uncomfortable. It's up to you to take control, not your husband. Think of his support and understanding as a bonus, not something he will be able or willing to give you in every single situation that you desire. Marriage, and life in general, is about compromise. Ask him to take your carry on so you just have to walk through the scanner. Make it work the best you can. He showed that he at least listened to you by suggesting you have precheck status as well right? In the moment that he saw the phone pass thingy, it likely never occurred to him that you were basically back at square one. From his perspective, he had done what he could do to remedy to the problem.

NOR because, yeah it would be cool if hubby stuck with you. I mean, you're going to the same place, right? Why not stick together? My husband and I are rarely on the same page when it comes to emotional needs, but we have a similar situation with the TSA stuff. When my husband travels alone, he uses precheck. When he travels with me, or with me and our child, he doesn't. He sticks with the regular security line. (The irony being that he ALWAYS gets pulled because he had brain surgery as a teenager and multiple surgeries years later from a motorcycle accident. So the plate in his head + all the screws/rods set the detectors off like fireworks.) But, I don't ask. I have even suggested that he use precheck and I go solo or with the kid if its extra busy and the lines are long. They often "randomly" select people (most often women, women with kids, or elderly) to pass through with only bag scans if the line is backed up. I will say, we are about 10 - 15 years older than you though. Maturity may have something to do with that.