Good for you for breaking up with a girl that cheated on you. Her cheating on you can affect you for awhile after. Your self esteem is lower, you are leery of new girls and new relationships. It is going to take some more time. I would suggest going out with friends, and chatting with girls very simply and easily. Small talk. Smile friendly. Just say "Hello"! If you force a date or force a new relationship, it might not go so well because you are not really ready yet, even though you *think* you are ready. In my personal experience, my longest and most successful relationships came from when I wasn't even looking for one. So, maybe don't look for one. Girls can sense desperation, too. And, please don't compare yourself to other couples that "look so happy". No relationship is all happy and sunshine and rainbows. You don't always know what is going on behind closed doors. Some couples only act happy in public. Please don't worry about how they look, just keep concentrating on yourself, and bettering yourself. Maybe try meetup or something similar, where there is no pressure to find a date. You can do this! It just takes a little time and a little effort on your part, to break out of your shell.

Also remember that the one doing the cheating is the one with issues. Be it lower morals, self esteem, or poorer communication skills (even intelligence), it’s not you. A wise man advised here to repeat a little mantra to yourself: Not my monkey, not my problem. Free yourself from her issues. Be yourself and learn and grow. The right one will appear one day. She might even have been hurt like you and is ready for a relationship where you actually discuss temptations when they come up instead of selfishly acting on them.

Psychologist say the best way to attract someone of the opposite sex is to focus on yourself. Sounds counterproductive, doesn't it?
But, women notice when a guy is strong and healthy mentally. To get there, all you need to do is focus on yourself. Take up hobbies, hang out casually with friends...find your sense of humour to openly flirt again. Girls love that!
Best of luck to you!

I appreciate everyone replying to my post positively. I have been trying to "be myself" more at work. I have noticed that fellow women coworkers are more willing to start a conversation with me because of my friendliness to everyone. I understand that I did the right thing to break up with my ex because cheating should not be tolerated. I don't think anyone should decide to cheat because they do not feel they are getting enough attention. If someone feels that it is not working anymore, then they need to sit down with their partner and try to make it work once again. If it does not work after that, it is best to go ahead and break it off rather than cheat. Her cheating on me will affect me for the rest of my life. There will not be a day that I don't think about her and miss her. I miss my ex every day but I know that what she did will live with her for the rest of her life. I often think of her and really miss her at times but I stay busy because I know if she is the true one for me, she will be back and want to make things better. However, I am not waiting on her because I know that I am valuable to someone who knows my true worth.

Hopefully that’s YOU too. And one day you won’t think about it. Trust me on this. How long that takes depends on how long you are going to keep it alive in your mind. Stay strong in you. If anything use this to gain maturity and insight.