By
eHow Relationships & Family Editor
Difficulty: Moderately Easy
Step1
Follow your instincts. A woman's intuition can be trusted most of the time. If you have a gut feeling that your boyfriend is cheating, he probably is up to no good.
Step2
Look at the history on the computer and his cell phone. Check text messages and the call history if he hasn't erased it. If you get a bill for the cell phone, check the call list for phone numbers that stand out.
Step3
Notice if he has changed things about himself suddenly. If he starts dieting, working out, buying new clothes, styling his hair differently or wearing new cologne, he may be cheating.
Step4
Follow him after work if he tells you he has to work late. Make sure he doesn't see you or your car. Working late is a popular excuse for cheaters.
Step5
Hire a private investigator if you think he is cheating but can't catch him yourself. An investigator will follow him and get you proof if he is cheating.