Gay: Sex...argh!

I don't think I can do it anymore. Because it just doesn't compare to what I had before. Maybe if I was actually attracted to someone and had built a relationship with that person, I'd feel differently. As it stands, I meet up with one night stands and "friends with benefits" and everytime I'm disappointed because it's just unsatisfying. Worse, I constantly think of my ex when I'm having sex and thinking back to how good our sex life was. It's comically ridiculous that I can't shake my feelings for this guy. Why is he so different? I dunno but in the meantime, I'm letting him keep me from enjoying myself. Goddamit.