My boyfriend (26M) genuinely wants to make me happy (25F), but he keeps missing the mark. How can I keep putting in effort when I'm not satisfied? What’s the best way to talk to him about this?

We began dating about three years ago and are now living together. We've been cohabiting for around three months, and unfortunately, our sex life is at its lowest point ever. Three years ago, it was nearly as bad, but we managed to work through it, and there were better moments in bed during our time together. He was the first to help me reach orgasm and genuinely tried to understand what I enjoy in bed, yet he still often forgets. Lately, he’s been finishing so quickly that I’m unable to enjoy the experience at all, and afterward, he feels disappointed and upset for not being able to satisfy me. It has even gotten to the point where I’ve found myself laughing at the awkwardness of it all, even though I know that might not be the best response. I feel like his lack of physical activity outside the bedroom and his dwindling confidence are impacting our intimacy. He’s requested that I not say “don’t stop” during sex, which leaves me unsure of how to express my desires; it feels like I’m just begging for more. Sometimes he starts off slowly, which can feel uncomfortable and off-putting. I’ve tried to communicate this, but he insists he just needs time to “get in the zone.” He struggles to maintain eye contact during sex, and our moments of connection are brief. I’ve expressed a desire to explore my sexuality and try new things, but we haven't ventured into that territory at all. While he has encouraged me to take more initiative, my attempts in the past often lead to him finishing even faster. It feels like I have to suppress parts of myself just to be intimate with him, and I’m unsure how much longer I can manage this. I’ve noticed that I've been relying on my vibrator quite a bit when I’m home alone, and I occasionally watch porn because I feel so turned on. It seems like he’s trying so hard and overthinking everything that he ends up failing. I’m not sure if I’m articulating this clearly, but I wonder if anyone else has experienced something similar with their partner.