Emily is a friend of mine I traveled with. She's the most independent person I know, she crossed the desert with myself and a group of others on camel back, and became the first wheelchair user to do so.
She knows what she's talking about with this stuff, give her blog a read, you might get a little bit of insight.
This post is particularly topical.
And my personal opinion:
*Yes, of course you shouldn't feel bad for not wanting to date somebody in a wheel chair, you have no emotional investment in this guy yet and I assume the feeling's mutual. However, there was no need for this, real situation or not, if you feel bad then nothing anybody can say on here will make you feel better, and if everybody says "oh yes, you're a terrible person, give the poor guy a chance" then obviously you aren't just going to change your mind because why would to date somebody you don't want to date? (that is, assuming you've got any sense about you)
*No, of course he shouldn't have said anything beforehand, that's perfectly his own choice. It isn't selfish of him, he's well within his own rights. And like Toffeelatteplease said, I assume you don't list your own physical status on the website?
*Just like the general consensus, the assumption that 'sex would be impossible' is ignorant, uneducated and just down right insulting. Perhaps he might not suddenly turn into Magic Mike as soon as the curtains close, but it's not all about the effort he would put in.
Overall: please raise your self awareness about how people in wheel chairs are just that: people in wheelchairs.