Please help! things are changing in my relationship

Hey everyone! I really need your advice

To begin with, I am someone who's experienced some emotional neglect in my childhood which affected me a lot (some of the consequences are: to feel stressed easily and the difficulty to talk about my thoughts and needs even defending myself and claiming my rights) then I met that better guy around three years ago after two failed relationships (I never really experienced a close relationship with my exes) and we fell in love quickly. Then he told me struggles with severe depression and OCD and I accepted him and I knew that relationship would be a long-distance one as well! and I was okay with that since I had enough patience especially since I saw him as a person with a unique personality.

As you know, LDR is not easy no matter how you two are healthy and loyal, and we faced a lot of challenges since the beginning but communication was always key even during arguments we've had, and he would tell me that I am someone to love and cherish and asked me to let him know about anything I could be uncomfortable with (I have experienced s**ual harassment by a someone older when I was a teen), and he would show me his love in various sweet ways despite his issues. It has been around two years since we started having physical things including sending n*des and it always was under my consentement, he would show me so much affection and admiration which is amazing.

As time goes by, we faced a lot of problems because of what we lacked as one of the effects of the long-distance, something that wouldn't help him mentally adding to it the pressure he's having at his job (he works over eight hours a day just to let you know) so he became more into the physical side of the relationship. I just started to feel "not okay" with it but I am being hesitant to say no, so I end up saying yes and do it while I try to hide any expression of rejection or something because I'm afraid he'd sleep frustrated or anything worse -who knows- like watching porn even though we both are against it, plus I miss the love he loved me before getting to see my body. On the other hand, I really hate that coward side of me that prevents me to live with more self-respect and peace of mind...

I don’t want to act rudely and neglect this kind of need of his but my uncomfortable feeling is getting stronger the more often he is asking for these things. Please help! I don't want to be fake with myself and anyone else, and mostly not hurt him.