Like all others, it is evident for you to feel heartbroken after your partner cheated on you. It is a tough time in your life and it is very difficult to cope with. Neverthless, getting your ex back or giving up him/her after cheating is completely your choice. It is important that you need to consider carefully and don't hurry to give any decision.
Obviously you still love your ex, or you wouldn't be so cut up about the situation. The thing is, the trust that you once had in your ex has now all but disappeared. You also have many questions floating around your mind, such as how long was the affair going on, and why did your ex cheat on you. These things will leave you doubting as to your ex's loyalty to you during your relationship.
The affair will also have had a detrimental effect on your self-confidence as well. For instance, if your ex resorted to cheating on you, surely it was because you weren't good enough for him/her? As you can see, a lot of thought has to go into making a concrete decision to get your ex back after cheating.
Another thing, if you and your ex decide to give your relationship another try, you must be prepared for a very long road ahead. You might be blissfully happy to have your ex back in your life again, but is your happiness going to be all round? For instance, if your ex says that he/she has to work late one evening can he/she be trusted? Is there really an overload of work at the office, or is your ex going to meet someone else?
If your ex is talking on the phone then that too will be cause for suspicion.