I never cheated on my husband, but I have seen others do it. Most of the time, it is a cry for attention.
Boredom or neglect in the bedroom, Poor personal hygiene or working at the job too much are more causes.
Cheating is very obvious. People let their marriages go stale and it dies slowly day by day until one day you wake up and think "I don't want to spend the rest of my life with this person.'