Having someone cheat on you is truly the ultimate betrayal.  There is nothing worse than caring deeply for someone and finding out that they have been with someone behind your back.  If you ever find out that someone has been untrue to you it can be a high hurdle to get over.  Other than email, the only way they would be able to communicate with someone else is via text and calling on their phone.

You can have a private investigator obtain their phone records which would show not only the dates, times and numbers coming and going to their cell phone but also text and picture messages.  Once you have checked out their phone records you can be sure whether they are having an affair or not.  For most people, even if they are in a long-term relationship and trying to keep their affair secret, do not stop to consider that their phone calls and messages could be used against them at a later date.  If you are pretty sure that your spouse is cheating and want to hire a private investigator to obtain their phone records for proof, now it will just be a matter of knowing who to hire.

Make sure that you keep a low profile if you are going through to get private investigator phone records.   Now you just need to find a private detective that you can trust in and make sure you keep a low profile.  This is a popular online private detective site where you just need a credit card and a couple hundred dollars to burn to get the information that you need.   Even if you are almost positive that your spouse is cheating if you are not sure, the last thing you want is for them to find out that you are going behind their back to find out.

Let them know the name and number of your partner and they will be able to do a search.  Some people have issues with trust and especially if you have been in situations before where you were treated bad and cheated on, you are much more likely to assume your future partners are cheating as well.  Just because you have a suspicion and phone records may seem to agree with you, you still want to be absolutely sure before you accuse them of anything.   Using the private investigator phone records if you feel that they align with your story and prove they are cheating, you can feel safe confronting them.

If they come clean and admit what they have been doing then you will have a whole new set of things to worry about.  You are going to need to decide whether or not the relationship is even worth trying to save. It can be hard to move on and forgive a person who has been unfaithful to you.    If you are both willing to give it a shot and try to mend things, it is going to be quite the challenge.