1. Are you watching his wallet? What kind of receipts do you find in there? Are there receipts to restaurants, motels, for clothing or jewelry? Any receipts that are out of the ordinary should be suspicious. This may be the place that he spent the money, what he spent the money on or what TIME he spent the money. All can be clues to his cheating.

2. Has his attitude changed? Is there a sudden and negative attitude change? If you notice that he is quite a bit more touchy and/or standoffish than usual, it may be time to do some digging. If this is just occurring without any real reason, chances are something else is going on.

3. Are you watching his email? This one is simple. Are there addresses in his address book that just don't seem right? Such as candisweethrt(at)aol.com, this type of address should raise suspicion in even the most devoted girlfriend. If you find addresses like this it is time to do some digging.

4. How does he act with other women? How does he act with other women? Is he very flirtatious and touchy with them? Does he need female attention when he is out in public? If this is the case, you need to keep a very close eye on him as he is most likely trying to lay ground work for future interactions.

5. Has your sex life changed? Has there been a drastic change in the amount of sex your having and the intimacy during love making? Is he just going through the motions? Has it stopped completely? Do you feel like he just doesn't care about having sex anymore? If so, then this may be a very prominent sign that something is going on outside of your bedroom.