Vintage cat I can relate. I have always been the one to make fun of myself first even though it was funny, it did make some in my company uncomfortable.
I agree with the "security" blanket idea. For some reason when I am not in a relationship I can be a size 6. As soon as I am in a serious relationship, I blow up like a balloon. I was just married 2 years ago and feel like such a fraud because I was a size 8 when I met my husband, now Im a 16.
I am trying really hard now because as understanding and loving as my husband is, he thinks I am deeply unhappy with him.

This is such an interesting topic and I totally have those feelings, even though I'm still in the 220s. I'll see myself in the mirror at the gym and think, "Where am I? I'm wasting away!" Hardly! :D

Wendyg, I have totally been the same way, gaining 100 pounds with EACH of my serious relationships and then dropping the weight pretty easily after the break up. I was a size 10 when I met my husband. In January this year, I was a size 22/24 and felt the same way that you described (I'm finally back in a 16, though!). It's so hard to carry that guilt.