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

Forgiving Infidelity - Is It Really Possible To Forgive?

Discovering that your partner has been unfaithful to you is a traumatic experience and one from which you think your will never recover emotionally. However, forgiving infidelity is a necessary part of the healing process in order to rebuild your relationship and become the loving couple that you once were. There is no doubt that you will be angry at first and probably say some things that you will later regret. This is because the person you trusted most in your life has mishandled that trust and thrown it back in your face.

When you find out about the infidelity and confront your spouse with it, the best thing to do is put some distance between you after the confrontation. This will give both of you time to cool down so you can talk things over rationally. This calm talk is essential for you to understand why the affair happened in the first place and how you plan to proceed with your relationship. During your fight, and there is a good chance there was a fight, your partner may have expressed sorrow at having the affair.

This is the start and it is important that he/she apologize for having strayed and hurt you. Once the apology is out in the open you can start down the road to forgiveness, even though it will be a rocky one at first. Then you have to see if there is a renewed commitment on both your parts to get past this and move on. Your spouse has to agree to stop the affair immediately by severing all ties with the lover. This may be harder for you to believer or accept if the other person was a coworker with whom your spouse will still have contact. You will need assurances that all future contact will be for business only.

The manner in which you discovered the affair will have an affect on the forgiveness process. If you caught your spouse in the act, it will be harder to forgive than if he/she came clean and admitted it to you when you were alone. If you had a feeling that the affair had been going on and your spouse was sneaking around while you collected the evidence to confront him/her with, will also affect how readily you can forgive the infidelity. You also have to look into the apology to determine if your spouse is sorry for having had the affair or if the apology is for getting caught.

Think about how you feel about your spouse now. Are you still in love? If so, then there is a great chance you will be able to forgive the unfaithfulness. However, if you have doubts about your feelings, then it may be harder to forgive and get over the hurt you feel. Your love isn’t enough though. You have to find out if your spouse is still in love with you and does want to make an effort to make things better. If your spouse is angry with you for having discovered the affair, then maybe your relationship is over.