What is my problem? Losing, Gaining, Losing.. Gaining?

I want to hear from those who have had a similar path as me. Its been an ongoing battle of motivation to lose weight, when I really got my butt in gear a year ago, I went from 230 lbs to 201lbs in a few months. I couldn't wait until I got below the 200s, and somewhere along the way I started reverting back to my old ways and gaining the weight back. Is there any advice on how you stuck with it til the end?