Why some men flirt and try to have sex with other girls/women even when have pretty wife at home?

I think it's when they are insecure about need the conquest to prove themselves as men but sometimes it's just about the sex, if they are not getting it or the sex with their wife is boring and unfulfilling.

Probably for the same reasons some women do the same thing. You never know what's really going on behind closed doors.

Sometimes the desire goes away but the convenience remains.

Some people get what they want and don't want it anymore. Some people need a constant challenge. For them, the thrill is in the chase, not the kill. The kill becomes a foregone conclusion while they're steadily scanning their sector for more prey.

Maybe they think they're invincible and will never be caught and never admit it if they are. The only way you can possibly make a cheater stop cheating is to leave them and never return. That might possibly make them stop cheating on the next one. But they're always going to cheat on you once they start

Hoggin it ALL up for themselves.

They are the type that will use anything that comes along

Because they're unwise and ungrateful.

STRONG libido !?