Firstly, however, think long and hard about whether you really want to know if your spouse is cheating on you:
It can be horrendous to think that your spouse may be cheating on you behind your back. However, it can be even more devastating to catch them at it. You should think long and hard before taking steps to catch a cheating spouse.
Ask yourself if you are really prepared to find out that your spouse is cheating on you. Think about how it will make you feel and how it will affect your life. Are you sure you really want to know? What will you do if your fears are confirmed and your spouse is cheating on you? Will you want to try and rescue your marriage, for instance, or get a divorce?
Getting divorced and starting a new life is a huge change for anyone to consider. Also, if you do catch your spouse cheating, it may prompt them to instigate a divorce that you don't want. They may have been happy to maintain the status quo previously, but being found out might actually come as a relief to them. They may permanently switch to the other partner when they wouldn't necessarily have done so otherwise.
If you and your spouse have children together, you may want to consider how it will affect them if you catch your spouse cheating on you. Even if you and your spouse end up staying together and your children don't find out about the affair, the effect your discovery will have on your relationship will most likely affect them indirectly.
You shouldn't let concerns about your children stop you, however, if you do want to catch out a cheating spouse. After all, the suspicion that your spouse may be having an affair probably already makes you unhappy. If your unhappiness is affecting your children, it may be best to find out for sure if your spouse is cheating and move on. However, it is always best to consider in advance how you will cope with your children's needs and feelings if your suspicions are confirmed.
If you do want to know if your spouse is cheating on you, start investigating:
Study changes in your spouse's behavior:
You have probably already picked up on some differences in the way your spouse behaves. This is probably what has alerted you to the possibility that they may be having an affair.
Especially early on in an affair, most people feel guilty about cheating on their partner and often compensate by being especially loving or generous toward them. If your spouse is suddenly giving you unexpected gifts or being uncharacteristically attentive and kind toward you, it may be a sign that they are cheating on you.
Examine your spouse's recent schedule. Has your spouse been going on more business trips than usual or working late more often? If you are seeing less of your spouse than you would normally it may be that they may be spending this time with another partner.
Is your spouse paying more attention to his, or her, personal appearance than they would normally? If your spouse is suddenly sprucing theirself up with new clothes and perfume, or aftershave, this could be for someone else's benefit.
Your spouse may also show less interest in you sexually, although this isn't always the case. However, if a sudden disinterest in love-making coincides with other suspicious behavior, it could be another sign that they are having an affair.
Look for further evidence:
Read your spouse's cell phone bill. Take note of any numbers they have called on their phone that you think are suspicious. Calls made during the times when they are on their way to and from work might well be to another lover. See if they regularly make calls to the same number during these times.
Look at your spouse's current spending habits. Are they making unusual purchases or drawing sums of cash from your joint account that they wouldn't do normally? Analyze any receipts that you find in their wallet, purse, or pockets. Do the receipts correspond with what your spouse tells you they have been doing, or does it seem like they have been up to something else? If your spouse is having an affair, the times and dates on receipts may not tally with what you have been told. Also, you may find receipts, or transactions on credit card statements, for things like hotel bills, or meals in restaurants, that you know aren't work related.
Simply studying your spouse's dirty laundry may provide further evidence that they may be cheating on you. A lipstick stain on a man's shirt collar, or the smell of a non-familiar aftershave on a woman's dress, can be a dead give away that something is not right. Don't jump to conclusions, however. There may be an innocent explanation for these things and you need a lot more evidence to be sure that your spouse is cheating on you. If you frequently are made suspicious by these kind of things though, your suspicions that your spouse is having an affair are probably right.
Recording the changing mileage on your spouse's vehicle daily, or taking note if they are buying more fuel than normal, can also offer valuable insight into what they are up to when away from home. If they are suddenly traveling further than they used to, or doing more miles than you think they need to, it could be that they are making regular trips to see another partner.
Compile plenty of evidence before taking things further. You don't want to risk damaging your relationship with unfair accusations.
If you become convinced that your spouse is cheating on you, it's time to discover the truth:
There are various ways of going about this and how you decide to do it is up to you.
You could discreetly follow your spouse yourself to find what they are up to while away from home. This is potentially problematic, however. If they spot you and find out you that you think they are cheating on you, it may cause a row or alert them to the risk of being caught. They may then take steps to avoid being caught in future.
You could hire a private detective. While this is an expensive option, professional investigators can usually discover the truth more quickly than you can alone. They are also more able to obtain photographic evidence, for example, that can help you to prove that your spouse is cheating on you. Hiring a private detective also means that you avoid potentially unpleasant confrontations with your spouse's partner. It may also be less harmful to you emotionally to let someone else take over at this stage.
Depending on how much you love your spouse, and how well you get on with them, you may simply want to ask them if they are having an affair. Explain your suspicions and see how they react. They may actually be keen to confess once they realize you already suspect they are being unfaithful to you. Even if they don't confess to the affair, if they are caught off guard, they will be less able to talk their way around your list of evidence.
Confronting your spouse: