my anxiety issues

I have been diagnosed with generalized anxiety disorder and I am handling it reasonably well with medicine, although I tend to come across as shy in public and I can obsess about small things. My husband says he fully understands and that it's not an issue to him, but every time we socialize I notice how much more composed other women are and I wonder if he would rather be with one of them, not me. I can't get it out of my head that I am holding him back. He is patient and assures me that we're good, but I can never get comfortable. I feel he deserves better even though he says I'm just right for him.

i would take your husband at his word and not fret about other women seeming more composed. you don't need to compare yourself to others, obviously your husband saw something in you that he wanted to marry you. go with the flow!

From what you described, your husband sounds like the kind of man who would talk things out with you. So don't just silently assume his thoughts. Talk with him about your feelings, even if you need to work with a counselor to get it all out. Then watch to see if his actions match his words. That is the best you can do.
The rest of the story is up to you. You can't get all your self esteem from him. Learn to believe in who you are.

I've also worried that I'm not outgoing enough until my counselor pointed out to me that not everyone wants to be tied to the ultimate extrovert. Variety is the spice of life and that includes personality types too. Embrace who you are as opposed to assuming you are supposed to be someone you are not.