My first guess is, the guy in the corner is thinking "I've banged this chick 500,000 times already. When I first met her I wanted her every second. Now, I am just bored of her and only give her the bone when I am super horny and really need to get laid. Otherwise I find TV to be more interesting than having sex with her. Which is why she is on cam naked and masturbating. My second guess is, he may also be thinking "That's my sister and therefore i'm not interested in banging her." I think i'll go with the first guess
