First - DON'T. Hating oneself bring no value to anyone and hurt you more. As a result you seek even more chances to increase self esteem, and unfortunately we find our lies as one of a shortcut methods (that however soon turns to be the worst choice and after short boost give as as hard kick back as possible).
Second - to me if you know that what you say or do is incorrect, if you deliberately don't say something to achieve some effect, to hide something - this is a lie. No matter how you judge the action itself. However if you truly believe that you're telling the truth even though later it turns out to be different - it's just a human mistake that anyone can do. We are only humans. We do mistakes. Our memory is as faulty as anyone else and sometimes we remember things that actually are just our imagination.
Always look inside of you. We might negate it but our conscientious is usually good at judging what is and what isn't a lie. We just hide it deep and don't want to listen. Change that - start listening to it and let it "speak" in your mind before you say the words aloud. And put effort (yes, it's an effort for us) to stop saying words when you conscientious tells you you're about to say a lie.
BUT if you already did... as soon as you realize that, immediately tell the person (especially those whom you love) that you lied. Let them know, you're trying to change, you don't WANT to do it.
At the beginning lying is difficult to get rid of it because it comes as a first thing to say (in our case, people who are not compulsive liars have first the honest answer and have to "invent" a lie). And we tend to say the first thing that comes to our mind. But if you regularly pause and start thinking over your answers you'll see after some time (in my case it was months, I don't know how many) that your thinking change back to "normal" - where honesty comes first. You'll still have a desire to tell the lie (that lies in us and I'm afraid will stay there forever) but as you need to put effort in lie it becomes more and more difficult.
Unfortunately I still can't say I never lie. Moreover I'm not sure I'll ever be able to say so. Sometimes it's stronger than me. But the change is so huge it's hard to imagine it could be done. And everyone can change like that - you too!
Remember - start with small steps. Everyday make a one day without lie. Soon they'll become months without planning it!
Hug to you!

Dito . And acceptance. You have to accept your past. Embrace it. But then let it go as you forge the new you. We manifest what we think around us. If you manifest hate in your self that is what the world brings us. Accept who you are and learn to love that person. You are enough. We will never be perfect because we are human. We all fall down! Everyone of us. It's ok to say I was wrong. I am going to change the choices I am making in my mind to become a healthier more whole hearted being. But to achieve a different way of living we have to change the choices we make in our minds that lead to choosing to lie instead of embracing the truth. I think I am "protecting my self image" when I lie rather than protecting someone else's feelings.

Thank you for the time in taking such wonderful responses and encouragement. While I was prepared to admit to a lie, I had to come clean. It was horrible to see the woman I lied to be in such pain. Why do I do this. What I had earlier in my mind justification of the lie to buy more time would have been less painful in the end the end. I'm an absolute mess now which doesn't compare I'm sure to how she feels. I accept who I am but this behavior I have been working on just feels so diluted at the moment.

Be patient. Change is going to take a lot of time. Your partner will probably not be very receptive at all to your effort, and will be skeptical. Accept that, and be patient. You are right... how you feel pales in comparison to how she feels, and as with my case, your feeling bad probably kind of hurts her further. She may think, or even ask, "Why do you feel bad? You did this."

I'm speaking from my experience.

- John. I'm a liar.

Thanks, John for the insights.

Ha! Wish I could heal mySELF.

Full of insight.
Learned and learning a lot.
Still fail miserably.

But thanks for the kudos, anyway. Glad to be of any help.