Maybe sex was the one thing that was really great during your relationship, and you have this weird idea that if you have sex with your ex, that it will fix things.
Obviously you and your ex have issues or you would not have broken up.
Jumping into bed with your ex is not going to solve these problems - they will still be there, even if you do get back together again because of sex.
Of course this means that before you know it, you are having another major argument and your relationship ends again - more anger, more heartache.
The bottom line is that sex with your ex, no matter how good it is, is not the way to get back together again.
What you and your ex need to do is to first take some time away from each other to let your anger and pain simmer down.
Once this has happened, THEN get together to talk about the problems you have and what you are going to do to fix them.
There is no way that having sex with your ex can solve the problems you have - only communication can achieve this.
If you still love each other deeply, then it is worth it to work through your problems one by one, solve them, and put them behind you.
Remember, it was the problems you have that caused the break up, and not because of the intimacy you experienced together.
Another reason why sex with your ex is not a good way to get back together again is respect - for yourself as well as your ex.
Having sex now will not prove that you still love each other.
You are in fact just using each other and this could very well cause even more heartache to both of you.
Don't make the mistake of thinking that sex with your ex will fix your break up.
Take things slowly and fix your problems first.
Get together with your ex, talk about the problems you have that caused you to break up, and work out ways together how you can avoid those problems in the future.
This will ease the tension between the two of you and prove your willingness to make each other happy.