he can't get me off

my boyfriend and I have been dating for a year and two months and in that entire time, he hasn't been able to get me off. when he fingers me, he does the exact same thing I do when I masturbate (bc I showed him what to do) and still nothing. he fingered me for over half an hour one time and it still didn't work. he feels bad about it and so do I because I know it isn't his fault. anyone else ever have a similar problem?