I have a strange fetish I cant understand...........?

Ok this is weird but I feel like I need help and I'm too embarassed to tell anyone about this fetish which is so strange that I cannot categorize it. The closest fetish I can see it being is a fat fetish but its different. Let me try to explain. Ever since I was about 11, I get turned on whenever I see a very heavy guy walking by a large sized women, especially if he is larger than her. Also, when I pass these larger woman by, I want them to see that I am larger than them (even know Im not). If you think that's crazy and makes no sense, I wear a fat suit in public sometimes just so I can walk by heavy women so they can see how big I am, and it turns me on. Its a comparison fetish if anything. Now, I don't stalk people and I'm not doing anything illegal-just really really weird. I would never do anything to them. Its "mental" rape if anything but only I am the one that knows that! To the full figured woman, I am just another fat guy waddling by. I am married with kids and a job so I have to "sneak" doing this when they are not around. I would could stop this feeling but I've felt this way for 0ver 30 years and its not going away anytime soon. I have a therapist and Im even too embarrased to tell her? Can anybody help me?