To catch a cheating spouse, it is important that you find significant proof of their activities before you go any further. To easily find out if your partner is cheating, you should look through their records which should yield the most evidence of cheating. In this case, their cell phone would be the best port of call as it will give you plenty of information to see if they are cheating or not. Because you will have the likes of incoming / outgoing calls, text messages and address book to find who your partner has been talking to, you should be able to gage a great deal of who your partner has been chatting to.