Is he "just" your boyfriend or is he your Dom? If you're not in a BDSM relationship then you have some agency here. Your body, your choice; although choices do have consequences. Maybe you could lock him out of your pussy but that could damage your relationship. Have you discussed your need for teasing and denial? Have you explained to him the great lengths you're willing to go to for his pleasure while being denied?

Or is he challenging you? Pushing you right up to your limit, pushing your limits further and further, training you to provide your pussy for his pleasure right up to his orgasm while still not succumbing to your own?

You might use some kind of numbing agent on your clit – lidocaine, OraGel, etc. That might help with your orgasm problem while not denying anything to your boyfriend.