Jafo I can tell you this right now - if you met the girl of your dreams tomorrow, you would become so involved in her world that 12 months would go by before you realised that you haven't spoken to your friends. Then after the "honeymoon period" is over and you are desperate for a night out with your friends, you would want them to still be there.
Basically - don't burn any bridges and don't cast aside friendships simply because they met a partner, because the older you get you will realise just how important those friendships are. Just be there for your friends whether they are in a relationship or not, and when it finally happens for you, you'll want them to be there for you too.
When I met my wife, I pretty much cut all my friends off - mainly at her behest (she couldn't tolerate me being mates with girls or have male friends who had girlfriends in case I tried it on with one of them. WTF? I know) but thanks to Facebook arriving I was able to keep in touch with them, rebuild the friendships and now I am single again, they are closer to me than ever. If I had lost them then god knows where I'd be today.
You can maintain friendships while searching for love - don't see yourself as the "third wheel" - just see yourself as the free one, the one who can go anywhere and do anything he likes without having a partner who might not approve. Because deep down, sometimes your friends will wish they were in your shoes..