i am not divorced (may or may not be on my way), but my parents have been for 10 years. it is so true that marriage should not be your source of happiness; it is impossible. humans fail; it's in our nature. personally, i do think less of someone who is divorced. it shows me that they do not take marriage seriously, so why would they later? i understand there are a million different reasons--and some good ones--that people get divorced. however, i take marriage as the ultimate sacrafice of love. it's a lifelong commitment. and you say "for better or for worse..." so you know what you're getting into. divorce is way too common and it saddens me.
as for your feelings towards your wife, it could be because of something completely unrelated and you have simply labeled it as your love has gone. stress, a change, the lure of being single, even unhappiness with yourself. i would greatly recommend looking back on why you married in the first place, the positives in your marriage, the positive possibilities, and what it would be like divorced--in reality, not whatever the world tells you. don't get me wrong--it is very possible that you would be happy divorced, but more than likely not nearly as happy if you were in a marriage where you gave it your all.