No huge words of wisdom here jayhawk1 but from what you said:
I found somebody I could love and loved me back. We've been married for nearly 5 years and it has been a fairly happy marriage. Our only problem seems to be the economy has been down almost all of the years we've been together. But through it all, I've remained employed and we've never gone without essentials. We don't seem to ever fight, although we've both vented our frustrations from time to time. But there is one nagging problem that plagues me...There is no doubt that my wife loves me more than I love her. Why is that? What's wrong with me?
I've often heard that love starts with the "self", to truly love someone else you must first love yourself. Then you feel complete and don't need another to complete you. Perhaps you could explore this more just the fact that you question something is wrong with you makes me wonder if that could be the problem. It's not a big problem and it is fixable.
In the meantime I can offer these words of wisdom.........act as if. Love is a verb do loving things and incorporate loving acts in yourself and your marriage will benefit. And good for you to recognize there is a problem and seek a solution.