Hi
You were together for over a year. Was she selfish in the relationship? You finished with her and she wants you to feel bad, that's why she's letting you know that lots of men who like her. It doesn't mean it's true. She just wants to hurt you like she was hurt. Don't let her get to you. The more you let her, the more she'll do it because it gives her power.
Take time for yourself and start believing that you deserve a good life with someone who appreciates you. Be yourself and start enjoying life again. Then you'll be able to see things from a "distance". You might still feel a lot for your ex, or you might realize you don't feel anything for her and that you're much happier without her. You'll be in control. Your ex might decide she's been stupid and want you back (once she realises that you're getting on fine without her). The thing is though, you'll be in charge of your emotions and your new life, and you can then decide if you want her to be part of it. Good luck.
Some couples split up and move on. Others get back together again. Sometimes they just need some help, like I did. And we're still together and happy.
http://www.togetbackyourex.org