Why do married men like to play around apart from the obvious?

Apart from obvious reasons why do married men like to play around with women?
I mean play with women’s feelings, there was a man I knew and he acted as if he was single, we chatted online and out of the blue he admitted he was still married.
It was frustrating because he claimed he and his wife were separated but turns out they aren’t after he was flirting and even wanted me to come over to his place!
Then he got annoyed when I called him out on it and said he was happy with her and I blocked him.

Why do people do this and think it’s ok to lie and hurt others and their feelings?

Why do married men like to play around apart from the obvious?
Post Opinion