Staying motivated

We are starting week 3 of P90, and it's starting to get a little boring, so we're figuring out ways to keep motivated. By the two of us working out together each day that helps, and adding some Wii tennis afterwards helps.

Knowing that I keep moving towards the direction I want helps, but, there needs to be more. Why is it that we start to make changes in our life, stick with it for a while, and then we have a hard time sticking with this new lifestyle? It's why resolutions "fail" right? What is it that we get "tired of?" I enjoy eating right, and I love working out, yet I seem to have problems sticking with it past January or February, then I go back around April, and it just goes up and down.

Why are we this way? That is what I am going to ponder for a while.