I think the one biggest thing that causes failure for women and fitness is the thought that if we start a fitness program we will loose weight and start looking like we did at 18, or like some woman we saw on TV.
I think the first thing all of us need to realize is that if we do it, we will feel better, and have a better attitude on life, and be healthier. Somehow, that isn't enough for many of the women I know. Most women I know give up on exercise the second it gets in the way of their very busy schedule of kids, hubby, grand-kids, hubby, parents, etc. After all, they aren't any thinner, so why bother?
I've exercised most of my life, more and more as the years have gone on. Unfortunately, it hasn't turned me into a thin woman (something I wasn't to begin with).
I just wish many people (male or female) would get out and exercise without the expectation that it is going to make you slim or get you back your youth or ....
And I wish people wouldn't assume that because you are overweight you DON'T workout. I'm quite overweight, but work out quite a bit.
If you do it to improve your attitude and feelings about yourself and life, rather than to lose weight or look better, you'll feel better and do better on your program.
Exercise because of a million other reasons, and leave how you look out of it. You'll have more success with staying in your workout program.