I'm not sure about everyone else, but I have found that I have put on weight over the course of my long term relationships. The first time, it was because I was miserable and using emotional eating as a coping strategy without realizing (never a good idea). I gained somewhere around 30 pounds over a 2-3 year period. Not good. The last time, my weight tended to fluctuate 20 pounds or so...I'd lose them and then I'd gain them back...then I'd lose them and gain them back...you get the picture.
When I moved home, I was close to being back to my heaviest weight after months of misery followed by a month or so of eating takeout while packing boxes to ship across the country. Again - I don't recommend that as a wise course of action, but sometimes it is necessary to do what needs to be done without losing your mind.
I am by no means fanatical about my weight, but I do try to stay healthy and in decent shape. As my mother says, "everything in moderation." I walk, I do yoga, I hike (none of which is done on stringently, but all of which occurs fairly frequently) and I attempt to eat healthy during the week so that the weekend splurges are not quite so guilt-ridden. And on that note, I am happy to report that I am now down to pre-last-boyfriend weight (on the button). And in another 10 pounds I will be down to pre-first-boyfriend weight...which I haven't been since I was 19-20ish. Now THAT is exciting :)
I also like to think of it as being symbolic...you know...like somehow the weight is connected to the emotional upheaval and baggage accumulated over the course of relationships that didn't work out and so losing it, in turn, equates to lightening the load on my mind and my shoulders and in my heart. I find it is therapeutic to look at it that way...as if I am working my way back to a sort of emotionally healthy tabula rasa state (in terms of healing old scars and banishing any bitterness/cynicism that may be lurking in parts unknown) for the right person to get a fair shot while maintaining all the lessons learned and wisdom garnered from the past...As someone said to me a few months ago, "We all have baggage. It's just a matter of learning to check it when you get on board the next flight and not dump it in the lap of the person sitting next to you." Wise words, indeed...