There are many reasons that lead to man wanting to find out about man else's marital history. If you are in a association and you want to find out if he is married, I can probably tell you a few ways in the paragraphs that follow.
For you to have asked this inquire your keen sense of alertness is telling you that something is wrong. So now you just have to more observant and more alert. I will tell you the things that you should look out for that are specific giveaways that a man is married. You will be able to tell all this by observing his behavior.
A guy who is not married will be very natural and free when he is with you. Are there places the he doesn't want the both of you to but goes on his own? Are there places that he likes avoiding being seen in? If a man is behaving like this then he is hiding something or from someone. Chances are he doesn't want you to find out if he is married. He might be having legal or financial problems as well but he should be able to discuss those with you.
Such behavior is top of the list for married man. You should watch him when he answers the phone. Does he always take his calls in private? If he claims its work related, then watch his body language when he is talking on the phone. Listen to the tone of his voice. It's very easy to tell the discrepancy in the middle of a business call and a call from someone's spouse.
If you can't confirm anything by observing the way he behaves but you honestly want to find out if he is married for sure. You can find out by accessing the public marriage records and check him out. You do not have to join a queue or fill out any forms. You can do it online.
Want to Find Out If He is Married? Here Are Some useful Tips