Deepblu: Welcome to 50... sucks, don't it? To me, it feels like, everything's on the table all of a sudden, stuck in an unending poker game that's getting progressively less entertaining, but there's no way out without folding... it's annoying.  
I ain't folding. Here's what I've done lately. First, I stopped generalizing my disappointment that I don't have a life partner. That does suck, and I am lonely, but I was letting that color my perception of the world in general, and it wasn't true. As I've opened myself to it, I've realized that my world is actually filled with opportunities for me to touch other people, and for me to touch them. Kind words and a smile to strangers you pass in stores and on the street. Encouragement to every person you run into who you can see is going out of their way to do a good job. Make yourself walk your neighborhood, and say hi to people in their yard, compliment their gardening, say hi to the kids racing past you. They may ignore you. Laugh at that. You were probably a punk once, yourself. After they see you around awhile, they'll say "hey" back. Has worked for me.
Interact with your world with positive energy, and you MAKE your world a positive place.
You'll get a lot of that positivity back, and it builds on itself. Now, truthfully, is it enough? No. Am I content? No. But, I'm less lonely, and I'm a whole lot less bitter.
Plus, hey? Maybe if we do enough good, God'll give us a break and let us have a relationship. Maybe it's a brownie point system. Who knows.
Hang tuff, bro.