On another note, Innovis, have you seen my threads on yeast infections and pain during intercourse? (Both in sexuality and in ladies' lounge). What your girl has sounds EXACTLY like a yeast infection... leads to very painful intercourse, like your dick has sandpaper covering it. Has she had it checked out?
Also, my jaw goes numb after 15-20 mins of a bj, too... LPM don't feel bad about that, either we aren't made for it, or it just takes practice... but I don't think that going down on a woman is the same as going down on a man, simply because of the lack of a big thick cylinder blocking the throat and creating a gag reflex. So Innovis I don't think it has much to do with "stamina," I want to give my bf the best bj's ever but my lips just go numb.
And LPM, I don't think any of us are blaming your bf, but we are not excluding him, either. You both have issues, as do most people in any relationship. I think both of you need to be in counseling, perhaps as a couple, before getting married. Please don't get angry or defensive about this... after all, you did come here for advice, right? Sexual incompatibility is a very serious thing to address before walking down the aisle, and I've seen couples who got married at your age get a divorce within a few years because of it. Neither of you wants to go through life resenting the other person, even a little bit, because of sexual problems.