My husband won’t go down on me and I don’t know how to communicate how much it hurts my feelings.

My lovely husband and I have been together for 3 years. He was my first in everything and he will be my last i cant imagine myself with any other person.
Our relationship is perfect except for the fact he won’t go down on me. I have tried to talk about it with him before, but our conversations just goes nowhere/in circles. It’s very sensitive part of our relationship. Here’s both sides of the argument:

His side – He is very particular about what goes in or on his mouth. (This is true because of other behaviors he has exhibited that aren’t related to sex.) He tells me the more I bring it up, the less he wants to do it because he feels pressured into doing something he doesn’t want to do. (I feel it’s important to mention I’ve only brought this topic up a max of 4 times). He tells me he might do it eventually and that we will see but I’ll have to maybe come to terms with him never doing it. He is also working with his therapist about these issues.

My side – I feel really hurt by this whole thing because I have gone through some trauma involving giving head. I worked through that trauma with him and he was very patient and understanding that it was difficult, but I got through it and now I go down on him and I’m really happy to do it because I want to make him feel good.

That was my driving factor with going down on him and pushing through the urge to want to gag and cry, because I wanted him to feel good. I also do not think it is fair of him to expect me to just be okay with the possibility that it will never happen in my life. I want to have that experience. At least one time.

I’ve thrown out options to where if he won’t do it, maybe I can find someone who will if he is okay with that. He says he isn’t. I guess I’m also hurt because he just doesn’t want to help me feel good.
I love my husband very much, but when we were talking the other day about sex, he mentioned how he really enjoyed oral sex because he could just really focus on the pleasure, and I found myself think bitterly
“Well, must be nice.”
I think I’m starting to resent him for it. Which is something I don’t want. I just want to know how to have a conversation with him without it turning into us just repeating ourselves. I just need some guidance.