One thing people should consider is that men can and will come nearly everytime they have sex. It's the norm: sex ends with the male climax. However, women struggle with climaxing for some reason. Now, why women struggle with orgasming, I don't know for sure. I've narrowed it down to a few reasons though. It may be that they've never had a guy that knows what he's doing or that they're not comfortable enough with themselves to let themselves have an orgasm. Also, some women just physically struggle with it--it's not they don't want to or are insecure or whathave you--their bodies are just not inclined. Most women (over 70 percent) will never reach climax purely from internal stimulation.
A lot of guys think that hammering away is going to get the girl off...with a small portion of women, this works. However, helping a woman achieve orgasm requires some work most of the time, and quite honestly, most guys just don't have the patience or the skills to do it, which helps explain the faking scenario discussed earlier.