My boyfriend dont want to have sex

So me and my boyfriend started talking a year ago, and ever since then we have had a really strong sexual chemistry. He has always made me feel really good about myself and made me regain the confidence I lost in my previous relationship. But the last couple of months he’s been giving me less compliments, whenever I send him “sexy” pictures he barely responds to them, and when I try to initiate sex he doesn’t seem in to it. We still have sex sometimes but It doesn’t feel the same. It seems like he wants to get it over with. He used to tell me how good it feels, how sexy I am and say I’m the best he’s ever been with. Now he doesn’t talk anymore and barely makes a sound. Yesterday I told him I was horny and he laughed a bit and said we could do it later, he used to tell me he would never say no to sex with me. Later in the evening I tried to make out with him and be sexy, but he actually told me to get away and laughed. I was so upset, but didn’t show it cause I want to respect his boundaries, and don’t want him to feel pressured to have sex with me. When we were going to sleep I asked him if he wanted to sleep or do something else first, but he said that he wasn’t horny right now. I can’t help but feel like there’s something wrong with me cause he’s never turned me down like that before, and with everything else I just feel like he doesn’t want me anymore and it’s really hurting me cause I’ve been through it before.

Can anyone relate or tell me how I can bring it up to him without sounding desperate or pressure him?