Sex with another person was in some ways disappointing when compared to masturbation and porn. I value emotional intimacy and you can't get that by masturbating, but if OP is interested purely in physical pleasure then he may in fact be better off on his own. Obviously your mileage may vary - lots of other people do enjoy casual sex so I guess they must get more than I would from it.

(I'm single now but in case a future partner sees this: you're different and I definitely enjoy sex with you more than anything else.)