Calling an ex after long spells of no talking might sometimes print a picture of desperation on you. You might still be hurting but trust me you will get over it. There is no point in trying to get them back. If they left then let them want to get back with you and not you forcing them back.
Do these 4 things whenever you are tempted to call/text your ex;
1. Remind yourself the wrong they did
They hurt you in the first place and that's why they are not with you. Whenever you are tempted to contact them, think of what wrong they did you.
Did they abandon you? Did they cheat? Did they lose interest in you? Collect yourself together and flood your mind with all these. You will put the phone aside.
2. Find things fun to do
If you love offering a helping hand then go out to the several orphanages around and help those needy children rather than force yourself on someone not worth you.
You can as well go to the gym, or go the movies with friends and have fun. Life is too short to force love.
3. Focus on your life
You were together but now you are alone. Why don't you focus on your life now and make it interesting than sit there thinking of how to please them again?
Life is never too nice to use the time you have to make yours nicest. You'll find someone.
4. Find people who love you and be with them
If he/she left you, there are other people who love you too. For the case of women, there are lots of men who love you and need you.
Spot one who you think can take that place and be with.
But beware because not everyone who shows you love actually loves you. Let no one use you. Men you can do the same.