My top pick for tips on how to catch cheating is this book by Sarah Paul

Getting Over An Affair - There Is No Easy Answer

Getting over an affair is a very stressful period in your life. You may actually wonder if you will ever get over it, but you will, one way or another. Once you discover that your partner has been unfaithful, you will feel a sense of loss - the loss of trust between you, a loss of love and a loss of your sense of self-worth. You will probably think that you did something wrong and quite often an affair does not have anything to do with the actions of the betrayed partner. Therefore, you need to put some space between you so that you can grieve. A grieving period is necessary in order to take the steps needed to move on.

First you have to reflect on your relationship and decide if it is worth saving. Think about how you feel about your partner and if there is still love there that can help salvage what you once had. This involves having a discussion with your cheating partner to discuss the reasons for the affair and why he/she allowed it to continue for the length of time it did. Once all this is out bin the open then you can discuss how you feel about each other.

The partner that was unfaithful has to make a sincere apology. You may be doubtful about this sincerity if you caught him/her in the act because it may be an apology for getting caught. If your partner admits the affair before you actually find out or before your suspicions are confirmed, you may feel better about the sincerity of the apology, especially if he/she says that the affair is already over. There have to be sincere promises that it won’t happen again. Even with these promises, it will take you time to get over the feeling of betrayal and it will take you time to trust your partner again.

You do have to let your feelings out - cry, rant, get angry. A release of feelings is necessary for the healing process to begin. Even though you may feel hurt and devastated, you do need to make sure you do not hurl accusations about other things or say things that you will later be sorry for saying. Once the words are out of your mouth, you cannot take them back. However, both of you need to let your frustrations out.

You do need to let your partner know that from now on there are boundaries for his actions. Let him/her know what you will and will not accept. If your partner is serious about mending the breach caused by the affair, he/she will agree to whatever terms you set, provided they are reasonable. You should not try to control your partner too much or you will drive him/her away forever. Above all, give yourself time. Don’t act in haste or do anything rash. Think about what brought you together and the love you once shared. This will help you get through the experience.