As the song goes, breaking up is hard to do. So does staying friends with the ex. Sure, there were good moments scattered in your memory that you do not want to do an "Eternal Sunshine of the Spotless Mind"on and these good thoughts are what you hang on to and hope that is just does not end there. You could still remain friends, and there are ways to remain that way no matter how bad the breakup was.
In order to move on, it is advisable to dispose all of the physical mementos that would make you go emo. If it helps you, delete the phonebook entry in your mobile. However, there might come a time that you need to contact your ex. Thanks to social networking sites, that was made easier.
What makes moving on hard for some is that they immediately make contact without letting off some steam. Hold your horses. This is where the adage time heals all wounds rings true. Let time pass. Keep yourself busy so that you do not end up wallowing. Learn a new hobby.
How much time should pass? Depends on how long and intimate the relationship and how messy the breakup was. Weeks are a definite no-no. You might be perceived as clinging. Some months would be good, at least a year would be better.
A simple message or email would suffice. Nothing grand and absolutely no "I miss you" and all that jazz. A simple "Hi, how are you?" would suffice. There would be awkward moments at the start, but you could breath easy if your former partner takes it well.
Keep things light and civil. Your objective is to remain friends, not to get back together again. In the same vein, determine your limits, especially if either of you have a relationship going on at the moment.
Speaking of current relationships, if you plan to invite your ex to your wedding, make sure that you are in good terms and are in constant contact. Nothing is more red flag inducing than when your former partner receiving a wedding invitation coming from you after not hearing from you for a long time. Just to add, it would be best to talk about this with the hubby before doing anything rash.
Avoid discussions of the past. Have casual and light conversations. In certain cases where the both of you hit off well as mere friends, you could share deeper topics in times when either of you needs a crying shoulder. Since you already know each other in a more personal level, giving advice and knowing the right words to say in times of need would be easier.
Besides the obvious of holding on to that one good thought, why would one keep contact with someone you described at his worst as a "pig"or have expletives going her way the night you broke up? The answer there is you will never know when you might need him or her for some minor favor or as an acquaintance that you can count on. In the end, maybe you are indeed better off as friends and it is not actually a bad thing.