How do I get my wife to want affection?

I'm 29, my wife is 27. We've been married for over 4 years now and from the very start she has never been very affectionate. She always said that after we got married things would be different, they never really were. We've never had more than 5 or 6 times a month. I have a very strong drive, and hers seems non-existent. I love being affectionate, hugging, kissing, just holding each other, she sees this stuff as pointless or PDA (to be holding her hand). I feel like I've tried everything to please her and I feel like she does nothing to meet me half way. She simply doesn't ever really crave or understand what it means to want to satisfy me. I get the most satisfaction in by satisfying my partner, but with her its pretty much impossible because all she ever seem to want is for it to be over. Its driving me crazy, I cant live like this. I regret getting married to her every day (all because we have no life!) It seems stupid, like it shouldn't matter that much, but it does. I don't know what to do. I've heard other people have had this kind of problem, what is the solution? (aside from getting a divorce or cheating on her). Help.