My boyfriend gets mad at me for talking about sex

I (26f) have been dating my boyfriend (26m) for 6 months. Everything seemed great at first. But at some point I noticed he would show less interest in sex. We do have sex from time to time but it’s not as frequent as it used to be or he wouldn’t really get into pleasing me the same way. I thought it could be something that can be discussed and work on. But instead it ends up with him getting mad that I “have a problem with how we’re having sex”. I didn’t understand why he would get so mad about it since I would think generally any person would want to please their partner and want to know their concerns.

But what really threw me off is that we used to have fun talking about sex. What we were into and what we could try. Now I worry about upsetting him even bringing up the topic.

I do believe it may have started because I made a dumb comment saying, “I’ll die if you don’t fuck me”. Not thinking much of it, trying to be playful if anything. However, at some point he told me how he would feel worthless because he would feel like he was only used for sex because of his past relationships. I was surprised he would think that since I do like a lot about him aside from sex and I do try to show him how much i care for him. Even when he logically knows that’s true he still gets mad about the topic. He realize it’s not an issue with me but it’s something within himself that he has to deal with.

I don’t know if I should wait and hope he figures it out on his own or will it probably be best to let things go. Honestly, it wouldn’t bother me this much if he didn’t get so irritated whenever I try to talk things out. I want to understand more of his side on things but the questions i ask, the more upset he gets. Something that should feel normal talking a partner is the hardest thing to bring up. I don’t know if I’m being impatient or try too hard to be his therapist, wanting him to talk out why he’s getting upset about sex. But I do know in the process of him figuring it out it’s making me feel a bit more closed off with my feelings. I really dislike feeling that way about my partner.