In any case, do not quarrel with her ex-boyfriend, don't make him hysterical. Talk to him, explain that you would like to renew the relationship, but nothing more. Of course, it hardly will meet you. But at least he will know that he is dear to you and can count on old feelings from your side.
Don't tell anyone about how you're hurting. On the contrary, try to demonstrate their good mood. Often appears in the companies, communicate with friends. Men by nature hunters. And often they don't want what's happening. But the prey escaped they will pursue.
So pretend you are all well. Not be amiss, if he learns that you have a fan or fans. But here to make serious relationship is not worth it. Especially with his acquaintances or friends. He could not risk to discourage a woman from another man.
Try to change anything in appearance. Change hairstyle, hair color, pick up the eyelashes or the nails. If you have problems with weight, get active, start eating right. You need to improve your appearance and behavior. This will benefit you and your ex will look at you from the other side.
Make new friends, invent a new hobby. In General, make no evening passed alone in front of the TV. Try to smile, even if nobody sees. Even the great sages said to smile always, and then a smile will grow to the soul. Take advantage of this rule, and after a while your mood will always be good.
When a guy sees that you are not depressed, but rather flourished, his attitude towards you will change. Hard to realize that you lost something dear. So after some time he can get back to you. But even if not, you will have a new life. In which you will be able to build a new, more enjoyable relationship.