Only you can answer that. The temptation to stray for the married man could be too much to conduct a friendship. I would suggest making sure the married man gives full disclosure to his wife. This should keep things at home on an even keel and limit any temptation the man might have.
This kind of relationship certainly has the potential to work if both parties involved have a mutual respect for the institution of marriage and perhaps more importantly, are not particularly attracted to each other physically. However, be forewarned that there still exists potential for this seemingly platonic relationship to evolve.
Honestly, you are both asking for trouble with his wife if you pursue even an innocent friendship with one another. My advice is to keep space between you.
been there and to tell you frankly,emotions will be at stake,you will fall inlove with the man and he will fall for you also,but its the two of you who will decide if both of you want to take the risk.