Some women can have an orgasm from intercourse. Most cannot.
Different positions work for different women.
You'll KNOW when you have an orgasm. It's hard to miss.
How long a guy lasts changes from guy to guy.
I masturbate and I'm engaged. I'm sure married couples do it as well.
All you need to masturbate is to be in 'the mood' .. i think you know what i mean.
I'm sure the other gals will tell you more and answer your questions in different ways and try to help you as much as they can.