Is it normal..... cheating? i mean married man with single gal?

No, it's not normal for anyone, but shitty people, two timers and whores, human garbage. Yuck!

Doing things behind your wife's back? Playing with her trust? Not caring about her feelings? Look, if you don't like her then get a divorce, rather than cheating on her. It's not nice, dude. Not nice at all.

Married man with single girl - he's cheating. I guess that if it's only a one-night stand it can be forgiven.

If trust is gone from a relationship, then even love can not hold it together.

I Don't get it either.
Fun fact; I have, what I know of, never been cheated on but hearing about other scums has caused me to have a severe distrust in my partners xD

Sadly I feel like most humans are pathetic, disgusting and a waste of space.

Unhappy in your marriage? Leave and you may have all the whores you want to.

I can never understand why people cheat. Wouldn't it be better in the long run to just cut your losses and get a divorce?

Yes, it's normal. It's not moral or ethical. It's a shitty thing to do. Your wife deserves better than you. But considering how many people are doing it, I have to say that it is obviously normal.