I wish I could be one of those guys who is so head over heels for his wife that he would never think of cheating and just be thrilled to have his wife.
One thing I have learned about love is that it has two primary components, which I refer to as "passion" and "commitment" (used in this sense, the word "passion" refers to the sense of delight the lover finds in the beloved).
In the early part of a relationship, this is usually what feeds the commitment in the heart of the lover, but it never stays that way
--passion will always diminish over time unless the commitment has grown enough to where it now feeds the passion
When you speak about wanting to be "head over heels," you're speaking about a very intense passion. Many of us never experience this level of intensity, while for some it is strictly an illusion, but even in those cases where it is real, I believe that what keeps it alive is the commitment.
The good news is that you recognize the problem:
I wrecked a 16 year marriage to a wonderful woman (sweet, good Mom, good cook, pretty, nice figure, God loving) because I was always waiting for something better to come along.
Some people never get to that point, and spend the rest of their lives blaming others. Pray for them, and thank God He has given you a chance to be different!