If they have nothing to hide, adding a profile photo should not be a problem at all.
A married man is usually very cagey and does not like to reveal too many details about himself online.
Plus a married man is seldom looking for a long term relationship and they believe a casual fling is easier to find on a free dating site. One or two of these reasons alone cannot prove that you're chatting with a cheater.
However, if they test positive for four or more of these signs, he could very well be a married man simply looking for a way to cheat.
It's not that women don't do it; it's just that the men do it much more.
Of course they can always put up fake photos but they usually do not have a photo at all.
He is probably juggling a family life, work and other personal commitments along with his online life and has to schedule chatting with you based on the other not-so-secret parts of his life.
His responses may be erratic because he tries to fit in a quick email amidst the other busy aspects of his day or as mentioned above, he might be very regular and follow a strict pattern so keep an eye out.
I met all sorts of people, from all over the world, older and younger, and each seemingly as desperate for a true connection as I. Should I be blaming my mother, or my – mostly absent – father for feeling that something was eternally missing? I was born to a woman that didn't much want children, and who fell foul to postnatal depression a good couple of decades before the term was even coined.
And for a while at least, it all felt harmless and innocent, and fun. My father leaving didn't help, and for the first six months of my life I was placed with a notional "auntie", a family friend who became my surrogate mother throughout my childhood.