As a rule, a married man meets with you in any specific days of the week. He tells his wife that in those days, he was appointed an important meeting, or problems at work. Look at his passport (if the opportunity arises) - on the page "Marital status" you can see a stamp or the absence of it.
Holidays to your favorites can spend with your family. And you say that he had urgent business trip. If he stays with you for the night, then be sure to disable cell, as conversations with his wife bring him to clean water.
He often speaks on a mobile, moving in the direction where it will not be heard. Or even ignored calls from his wife. A man can answer, but quickly turn off the phone.
If this works out, then see how you are listed in his mobile phone. Perhaps, your number will be encrypted. Often married people names in the phone records mistresses male names.
A man with a family, do not you invite me to visit or to explore with parents. He is not your friends. Your visits usually take place at your home or hotel.
Give him underwear and observe whether the man wearing it. Wife interested in such a thing, since it is unlikely that her husband bought it yourself. Most likely, it will get rid of a gift or simply will not accept it.
Therefore, if the partner does not like to hear from you and we launched wearing donated things, it means a sign of psychological relationship with another person, or that a serious relationship, he is not ready yet. Thus, to be vigilant and do not allow yourself to cheat.