When you want to get back with him or her, sex with your ex is perhaps the WORST way to go about doing it.
The last thing you want to do is rebuild a relationship, and that relationship be purely physical and based on sex.
You want love, respect, and kindness from your ex, along with intimacy, not JUST the intimacy.
One of the best things you can do, so you can continue to respect yourself, is to avoid have sex with your ex once you've split.
It might be difficult, but both you and your ex will respect you more in the end for it.
You do not want to end up in a "friends with benefits" fiasco as this is not at all what you want, nor expect out of a relationship.
While intimacy is nice, and it IS important, it is only one small part of a relationship.
You have to build on other things as well and setting up a situation where you have sex with your ex, you are risking your heart and your pride.
Having sex with your ex can set you up for an emotional breakdown.
Remember, people have sex all the time for no other reason than that they enjoy it.
There is a good chance that, after the breakup, the sex will be just that to your ex - sex, plain and simple.
You may read more into the experience than her or she will and this will set you up for heartbreak.
They could be under the assumption that you are cool with a no-strings-attached fling, and that is the last thing you want.
Getting your ex back is no easy task and if you have sex with your ex, you will make this endeavor even more of a challenge.
Sex is only one aspect of a full and healthy relationship, and if you've split, the last thing you want to do is start with the sex part and hope the rest follows along later.
This is a recipe for disaster and heartbreak.
You do not want to be used, you want to be loved, to be respected, and this will not happen if you have sex with your ex.