This is a tricky question. I think both sexes have cheaters. However, it is in a man’s biological instincts to spread their seeds, so to speak. It is in a woman’s instincts to look for a mate that will stay with her. I have also noticed a ton of married men flirting with women.
I think it also depends on the age of the person. I find men about ten years my senior to be more attractive, because they are more mature in their thinking. Also, probably less likely to cheat.
To answer your question, I feel that young men probably cheat more than women. However, I think that middle aged women probably cheat just as much as younger men.