Funky orgasms

Lately I've been having some serious problems getting off. Now, for some background, I didn't have my first orgasm until I was 17. It never happened when I masturbated and I didn't even know what it was when it happened. Over time I found I could get off from being on top in the 69 position (which is how it first happened) but that eventually stopped. I bought my first vibrator about two years ago and it has been what has primarily gotten me off since. Until lately. My boyfriend insists I use it when we have sex so that I don't feel like I'm missing out and because he wants that for me, but for the past few weeks it just won't happen. It takes literally forever and I have no clue what's up with me. I'm not under any extra stress or anything. I just can't get off. I'm losing my mind! Someone help?!