I can sympathize with the obsession about it. I think obsessing about your weight, or about how you'll look, or goals that can really be reached or fulfilled is misleading.
When I dieted the last time around (and you'd think I'd have learned this from watching both my parents do the same thing many times over the years) I was so excited to hit my goal weight (I came within 10 lbs of it). I thought that when I got there, I could finally indulge every now and then and all that. And the truth is, I can indulge every now and then NOW. Nothing is going to change when I hit my goal weight. My outlook then shouldn't be any different then it is now. Sure, then I can give myself a 5 lb limit and say that when I gain 5 lbs from goal weight I can really re-focus on healthy eating and exercise and lose it again, but same goes for now. I need to eat healthy for the rest of my life. For myself I am counting calories and while I do hope to get to a point where I won't be logging calories every day, I know I will still need to look at the labels and still have that magical 1200 or 1400 number in my head, whatever my body feels satisfied with to maintain my goal weight.
When I regained the weight last time, I have found the discouragement has helped me this time around. I log my calories on fitday, and I log every single bad piece of cake or every single bad thanksgiving meal. I count it a victory that I am admitting to eating that food, and letting it count against my numbers for the day and my average for the week. Success for me is when I actually average around 1200 for a week. Sometimes I hit 1300 or so, and I feel okay that I didn't let myself go totally to the dogs for one day. Sometimes I have one really really bad day, but I know that I can still go back to being good the next day. I also count my success in continuing to exercise. Not because I want to lose weight or look good, but because I can feel my fitness level rising. Physical tasks are becoming easier for me, and I can feel my strength growing. I have gotten used to the fact that I will never be thin and that is not my goal. In fact, due to my failure last time, even when my scale says I've lost weight, I rarely consider it a true loss until I've seen it straight for 2 or 3 weeks, or until another loss after that lasts me another week I'll count the first. I know that any healthy amount less than what I was before is better for me, and I am focusing on the lifestyle.
Now on the matter of obsession (I know, you're tired of reading my novel) I obsess a lot. But not about weight. I think a lot all day about what I am going to eat for dinner, how many calories are in it, and how I can balance out my whole day's meals. I know one big meal during the day will leave me hungry later and vice versa. I also visit these forums a lot when I'm not too busy, and it is truly an addiction

But I think in an empowering way. The advice offered on here for all aspects of life is really priceless, and I think it's the part of my new lifestyle that really nurishes my soul. Anyways, those are just my thoughts on all of that.