Quite a lot of people hook up with their exes after the break up for different reasons. Having sex with an ex is often compared with junk food: it's nice and easy, but not good for your health (in this case, emotional health). Before jumping into your ex's bed, you need to weigh the pros and cons of having sex with your ex.
Pro. It is sex. Going from having regular sex to having no sex at all after a break up is not easy, and masturbation can only help so much. If you're not into rebound sex with random people, hooking up with your ex is an easy way out.
Con. It's prevents you from moving on. If you keep convincing yourself that it's just sex and there are no emotions involved, you're delusional. There is no “just sex” with your ex, especially when you've just broken up, because you have the history of emotional attachment. People who keep having sex with their exes are usually unable to get over them because they still feel as if they were in a relationship.
Pro. It is convenient. You don't have to go on dates, all you have to do is call or text them, meet and have sex. A typical booty call relationship.
Con. You're off the market. Convenience of a no-strings-attached sexual relationship with your ex prevents you from dating other people. Why bother going through the courting process and the awkward phase of getting used to a new partner if you can just have great sex?
Pro/Con. It's a familiar territory. You know how to make each other feel good and don't let awkward situations throw you for a loop. You're compatible (otherwise you wouldn't want to have sex again) and can get each other off. However, familiar also means boring. Don't expect the sex to be extraordinary, it will probably be the same old routine.
Pro/Con. Cuddling with a random hook up is weird; cuddling with your ex is OK. If you are an affectionate person who likes post-sex cuddles, hooking up with an ex is a good option. However, cuddling with them will also prevent you from moving on, because this is what couples do.
Pro/Con. You might want to give your relationship a second chance. You can never tell whether it is a good or bad idea until you try. Maybe you will be able to resolve your issues and be together forever. Maybe you will lose time trying to mend something that can't be mended and have an even nastier breakup. Be that as it may, great sex is not a valid reason to get back together.
As you see, almost every advantage of hooking up with your ex is also a disadvantage. Of course, the decision is yours to make, but we strongly recommend against having sex with your ex.