Seeing couples doesn't hurt, I barely notice them. What does hurt, however, is seeing single women I like, since I simply never figured out how to approach them as anything other than a friend. It always failed - if I was too careful, they saw me as friendly but not interested (I've been going out with some women I liked as friends for years without managing to take steps towards a relationship), and if I tried being more obvious, it failed badly. Could be things would've turned out differently if I was more obvious with the girls who just viewed me as friendly, and less with the other ones, but who knows. The one relationship I've had was with a girl who took the initiative herself, without any subtle hints that would otherwise fly by unnoticed. Or could be she tried that, got tired of being ignored and decided to change her strategy. More girls like her would make the world a far better place. But anyhow, next after seeing single women I like, the loneliness is worst when going to sleep or being alone when I'm in certain moods.