My boyfriend doesnt make me cum anymore?

my boyfriend was my first and everything was fantastic at first. I'd honestly cum even before if finished. it was great.

however now he can get me to the point where I'm about to climax but I never actually do. he tries really hard to satisfy me. I think he's starting to catch on that I'm not climaxing. he asks if I've cummed after sex sometimes. he'll even try to keep going at it after he's cum to finish me off...however it still doesn't work. I usually have to lie and say I have. I've also been taking orgasms a lot lately.

I don't know what to do. advice?