If there is undeniable proof, which means proof that CANNOT be denied, the there wouldn't be any doubters. why are we supposed to love something that doesn't exist? Belief isn't enough. You don't need religion or belief to have morality. I'm an atheist, more anti-religion actually, but I know that harming people is wrong, I know that lying and cheating is wrong, not because of a deity but because it's human nature. Doing something that makes you feel good isn't morality, morality is doing things that aren't bad, or doing good things in the proper place.
Sex is good, in fact sex is amazing but I'm not going to "get the horn" one day and start with my girlfriend in the middle of town.
Drinking alcohol is good, within certain limits, but I'm not going to sit in a busy area and get totally hammered just to make myself feel better.
Helping other people is great, I do it because I like seeing other people happy and making their life easier, not because a so called "all powerful being" says I must.