From my observation , men tend to cheat more. A lot of my friends and acquaintances have husband who cheated on them. I think it is so true that men are polygamous by nature. Though I hate it that when a man cheats it seems it is not a sin to do so, but a common thing to do for men. But when a woman cheats, society looks at her so low.
Although again, not that I am prude , but if a woman wants another man, then separate from your husband first, before you go for that man you want. At least, you were already separated.
But , whoever does it , sins. Period.