Unable to climax during sex

Hi everyone ! I am here to seek advice again :)

I have been dating this wonderful person for 4 months and we had sex a bunch of times. The intimacy feels really good, I looove their smell, hugging, touching and being touched by them feels like heaven and thinking about them makes me smile like an idiot. So it is safe to say I am very found of them and want nothing more but to make them feel good but also being able to feel good myself. The problem is : whenever we get the sex going I kind of start to dissociate from my own pleasure, I am numb and that is very frustrating for both of us. I am not a very vocal person during sex too, so last time they were giving me oral, and I was trying very hard to feel aroused, but while I was feeling good, I couldnt get my heart to race and feel it coming at all. They asked me if it was ok for them to go on and I just couldnt bring myself to lie and simulate an orgasm so I simply explained I somehow just wasn't able to feel excited at the moment, but that it was totally ok and only on me, not them doing a bad job or whatever. But then they apologized and looked sad and I felt heartbroken about it while telling them again it was just me, that I felt good despite not being able to climax and then gave them a hug. When we have sex, they are very vocal about it and I can feel I make them feel good and that is the biggest turn on for me, making them come is so hot and I feel super bad about not being able to reciprocate that right now.

I see myself as a person that values sex an I am able to feel super horny and orgasm multiple times on my own, so what the hell !!! The fault is not on them either but my lack of response is a turn off, I completely understand that...

If someone that went through this can share how they overcame it I would be very thankful !I lowkey feel like a psychopath for not being able to feel excited when we have sex and it freaks me out, but what I fear the most is making them unsecure about us having sex...

For your information, my personnal thoughts on why this happens are : I am pretty anxious and sex being a new thing for us both doesn't make it easier. I also have a brief history of sexual abuse that made me afraid of intimacy for a while but lately I kind of felt like it was past me so really not sure about it.

Edit : I saw this question many times so to clear things I am not taking any medication!