12 tell-tale signs that he's cheating on you:

1. He's broke because all of his cash is going to the other woman.
2. He's been putting you down lately or picking fights with you (this is a tactic they use to ease their guilt).
3. They get defensive if you question where they've been or ask about females that he has been spending time with.
4. The first thing he does when he gets home is take a shower.
5. He has all of a sudden been meticulous with keeping his physical appearance up.
6. He doesn't have a lot of time for you, and he may have told you he's "working late" on many occasions.
7. He goes out at night, a lot. He may use the out with "buddies" excuse. When he's out, his phone is off, and goes straight to voicemail.
8. He's been getting a lot of calls/texts lately. He may act like he's in a rush to get off the phone.
9. He puts a password on his phone.
10. He hasn't put a password on his phone and you notice a lot of unknown numbers. (Beware, men will list their other women as businesses or names of men so you won't second-guess the calls).
11. Your sex life is non-existent
12. He asks you where you are all of the time. You think he's being concerned. The reality is... he's making sure he won't get caught in the act.

If any of the above behaviors ( or anything else you may feel is "sketchy" has been happening for an extended period of time, its likely that he is cheating on you. I don't recommend confronting him off the bat. He will lie. Men lie through their teeth because the last thing they want is to be confronted by a female.