Why do I feel like crap?

Why do I feel like crap? I pose this question to the society which caused this. There are guys who will cuddle with a woman and fondle her breasts without a care in the world, because socially, its accepted as proper sexual contact. So, why is it every time I enter a relationship, even after admitting my preferences, after having reached 3rd base, after establishing our bodies are free for each other to enjoy. My hands are nervous, terrified even, to even scrape against her belly, to take a handful of her extra flesh, to run my fingers over her curves. I do it, she looks at me, and my mind crafts the illusion that she feels extremely awkward, I feel like a complete pervert, just for enjoying a different bodily feature. I feel brick after brick drop in my stomach, a migraine starts up, it lasts for weeks.

She isn't feeling awkward, she's open, she understands, but its a deep crimson shame I feel. I feel like crying, as though I let out something embarrassing, something that is evil out of me. But it isn't evil in the slightest. Why does this happen? Its social conditioning. From our earliest sexual memories, we see women caressed in all the right places, we hear about women being caressed in all the right places, and those body parts which are not mentioned, are despised, mocked, seen as ridiculous. A girl I'm in a relationship is eating, and I can't help but being turned on, she notices, and smiles, and I turn to stone, horrible feeling in the pit of my gut, I feel like crap, and its because society teaches us women shouldn't eat a lot, the secret to attractiveness and health is eating very little actual food, salad, salad, salad. She eats a burger and fries, and the fact its currently expanding her stomach, the fact the fat cells will coalesce into thicker layers on her skin. It gets me horny, she accepts it, but my head is held low.

It isn't fair, it isn't fair that our completely normal fantasy is destroyed because society sees no beauty but thin. We cannot even enjoy our private sexuality, it is still a source of pain. My current girlfriend will ask me to massage her stomach, she's more than cool with me grabbing her love handles and belly during sex, she has gained 30 pounds by accident, and plans to maintain her size, I rub her stomach so much shes picked up the habit, and will do it to tease me, she'll push it into me, eat sexually in front of me, she has let me belly fuck her for gods sake (For all those missing out, its pretty amazing, pro tip, the stomach rubs on the surface of the penis, penis does not enter belly fat or belly button, don't need any injuries). Shes done all this, shes started to slowly, very slowly show the first tendrils of developing a slight attraction to her size, she talks dirty to me talking about her curvaceous figure, she does so much to make me comfortable.....

.... but I still feel like crap. Its sad, its the old saying from 1984, If everyone, and everything believes a lie, and you know the truth, does that mean you're insane? Or does majority truly rule?.... I believe the truth, that any woman could be beautiful, but I've been conditioned, and there's no way out of it except time.