My obsession and comparison

One way to fight my obsessive thoughts is to realize that deep down it does matter.  That is an irony, but in a way, it helps me to cope.  It is a way of being honest yet can be a deceptive way.  I can be truthful yet realize that it could be a cause for me to perform a compulsion or two.  For instance, I think it only matters whenever I see someone who has a body that I always wanted.  That is a way of thinking that there is deep down inside of me that it matters.  I needed to know why that matters.  I am not gay but I like to look at other women's backside.  The root cause of that is low self-esteem.  What I don't want is a flat behind. Mine is small but wide.  I would like for mine to be curvier and stick out a little more.  I am just not proud of my body.  I have a behind which includes a stomach that hangs down.  Whenever I sit down, my stomach is on my lap.  I feel so ashamed.  How could I allow this to happen?  Yes, I have an autoimmune condition, but I know that it will take a while to lose weight.  I want to have a flat stomach; my health and over well-being are very important to me.  Ever since I was a teenager I have always compared myself to other people.  I have finally learned not to do that and to see myself for who I am.