You have to think about how you two broke up in the first place. If you were the one that broke up with her then she might be trying to get back at you and show you what you are missing. This is a natural reaction to have when you have been hurt as you want to show your ex that they have made a mistake and provoke a reaction from them.
So what if she was the one that broke up with you?
Truth is that she could well have moved on and had her eye on this new guy for a while. That is hard to hear, but you need to face up to this as one of the possibilities. If this is the case then it is best for you to cut your losses and move on. The worst thing that you could do is to make yourself look pathetic in front of her. Have some self respect and move on yourself. It may ache right now, but you shouldn't want to be with someone who disrespects you, you deserve better than this.
When did you break up?
Another reason that she could be dating someone else is because she is in a rebound, this still happens if she was the one that broke up with you. She could be desperate to prove to herself that she made the right decision and wants to move on as quickly as possible. This never works however. When you try to force yourself to get over someone it usually backfires on you. This is even more true when you involve another party and expect them to be the answer to all of the hurt that you are feeling. She will come to realise this after a while herself.
If you broke up a short time ago then this is a very common tactic that exes employ to try and get over someone. The truth of the matter is that rebound relationships don't last long at all. On average they only last between 6 and 8 weeks. It takes this amount of time to make your ex realise that they are still not over you and miss you.
What you should do
If you go in and interfere with her new relationship you will end up looking like a jealous stalker. It is best for you to give them both space and avoid them if you possibly can. Never let her think that you are angry or upset over her new romance as this will make her feel good about herself. Instead you have to do what she least expects and act as if you don't care at all. This will shock her and make her wonder if you ever loved her at all. Once she sees that getting into a new relationship does not make you jealous, she will question why she is doing it in the first place and soon end it.
win back her heart very easily.
I know that this sounds impossible right now, but you have to at least pretend if you want her to regret her decision. We all are attracted to people who are positive and who it feels good to be around. Let her see that you are busy with your life and happy for them both. Don't lay it on too thick however or it will be glaringly obvious what you are trying to do.
Your next steps
You can discover how to use text messages to make her long for you and miss the good times that you spent together. These texts are all based around female psychology and what makes them melt. Watch the free video presentation to your left and find out what you should be doing now!