Why be in a couple?
I fly the flag of singledom, almost daily. Because, it's not enough that I'm gay, vegan, and a pornographer. I'm single as well, which puts me into yet another group that I defend.
I don't think that single people, are, or should be, any less happy than those that are in a couple.
I know a lot of unhappy married (or partnered) people. Being with someone doesn't, by itself, mean you're happy.
If you're a single person who feels that happiness will only come when you find your one true love, well, then you're doomed. No, one person, is ever going to be everything to you. You need to be happy with just yourself first.
Plus, almost all people can be in a couple if they really wanted to be - all they have to do is follow my three words of advice "Lower Your Standards". But people don't always lower their standards - why? Because being single's not that bad, when compared with being partnered with Joe Schlump or Prissy Patty.
And, married people don't necessarily have more sex.
So, really, what's the big deal? Consistancy? Companionship?
Why not just get a dog?
