Taken me a little while to get the time today to read through all this, so sorry for being quiet. Thanks so much everyone, for offering your ideas, concerns, experiences and also for helping me understand a bit better about sexual preferences :) I really am a bit naive! and i've never been massively confident.
I do enjoy sex with DP, we have always enjoyed sex together and I don't think we are mismatched so much, and he definitely cares about me enjoying myself, he doesn't 'use' me in the slightest, and no, i think he likes to look at my face as well as my ass
. He's a good guy. I'll def have a chat with him, and we'll just have to have a little bit of experimenting, but i think good advice bertie not to approach it as a problem, as that will probably make him really paranoid and set us up to fail. I think he is entitled to his sexual preference, bit i will keep my eye out that there aren't any underlying problemos. But I also haven't just suddenly totally gone off sex how we used to have it, I just want more variety, yes, a little good old fashioned lovemaking!...so we'll have a little talk about that. It is good to know that some of you (men and ladies) out there are not into slow gentle sex, that it is normal :) and i think him losing his erection isn't that he doesn't like being with me, but a physical thing, maybe right about getting too used to fast wanking. Gonna have a chat with him about those long early morning showers he takes 
Was really hard for me to write this post, i am a wee bit shy on the whole sex front, and this is not a conversation I could have had in RL, so big big thank yous to you all!
anyfucker good point...i do think i worry that he has to have an orgasm...time to stop doing that!!
need to start thinking 'me me me' more!
I'll let you all know how we get on
but thanks, feeling confident about this now.