Is sex really a deal breaker 🥴?

Okay ladies so I need some advice. Me and my ex recently started talking again & he’s done everything to prove to me that he’s changed & I can honestly say he’s improved in so many thing that I hated when we were together BUT there’s a problem 🤦🏾‍♀️. Our sexual connection is completely gone/OFF . He never lasts anymore , he always gets his but I never get mine & it’s just too damn quick for me to actually fully enjoy it. We never had bad sex when we were together but now I don’t enjoy it at all & I felt so bad for telling him. He says he’s gonna try his best to fix it but idk how that’s possible. I mean we were talking about moving together & everything! Ik sex isn’t everything in a relationship but it’s a huge part of it for me & I’m a super horny sexual person & I haven’t even been horny with him anymore. It’s like my body is telling me to give up but I just really like him. Any suggestions ? Advice ?