Faking the big O

This is a bit TMI... but honestly I’ve been having trouble having an orgasm lately with my boyfriend. He’s able to give me them and everything , but lately I’ve been masturbating because he hasn’t been able to make it happen, and he doesn’t know because I’m too embarrassed to say anything. I fake it and pretend everything was amazing on my end . Don’t get me wrong he’s amazing and he’s not selfish but every time I get so close he either stops or moves or something happens . And ugh idk what to do or how to stop it from happening . I don’t want to hurt his feelings. Or for him to ever find out I’ve been faking them . What do I do??