Blimey, I've spent a lot of time worrying how much sexual chemistry I've had with a partner. If I didn't have PIV (G-spot) orgasm with them, I wouldn't carry on dating them, its a non-negotiable. I see it as "the glue" that binds you together and makes me want to have sex with them repeatedly.
I am also sadly shocked that so many women have long term relationships and say they don't mind not cuming this way and just like the intimacy. It sounds like a lot of women cant orgasm easily for anatomical reasons, although I suspect its also a mental block.
Just out of interest, if you find it hard to achieve orgasm with a partner, lets say without a vibrator, what do you think binds you sexually to keep the relationship alive and connected?