I have been dating my girlfriend for one year. The thought of her cheating on me has always bothered me... although it has never happened i think about it a lot. The more i thought about it, the more i came to the realization that the one thing that bothered me about it was the chance that whoever she cheated on me with might have a bigger penis than i do. If she had sex with another guy, and i had some way of knowing that he was my size or smaller, i would be angry and confront her but i wouldn't break up with her. The other guy would not be a threat to me in my head. If he had a larger penis than me, i would have to break up with her, sex with her would never be the same. I would always be thinking about how she had sex with another guy with a bigger dick then back to sex with me. I have no reason to be insecure about my penis. It is 6.5 inches long with 5.6 inch circumfrence... so its average or slightly above average depending on what data you believe. My girlfriend is a petite girl, i press against her cervix or kind of slide into the area right beneath her cervix (its not very big) in a lot of positions (missionary, cowgirl, ect). But for some reason, the idea of her cheating with a guy with a larger dick is unbearable, but the idea of her cheating with a smaller guy is not, its almost empowering. Is this normal? Any other guys in relationships feel this way? Its kind of the opposite of the whole cuckold fetish thing i guess. Am i just placing to much importance on penis size?